It wasn't the most exciting race in Spain but there was still plenty to talk about. Laurence Edmondson (F1 editor), Nate Saunders (F1 deputy editor) and ESPN columnists Kate Walker and Maurice Hamilton give their opinions on the main ones below.
Did Pirelli favour Mercedes by bringing thinner tread tyres to the Spanish GP?
Nate Saunders: No. Blistering was clearly a problem -- one which appeared to be most pronounced on the Mercedes -- to some degree for everyone during the winter tests. Pirelli's job is to ensure race tyres last the distance they are supposed to and the fact the modified tyres we saw in Spain will also be used at Silverstone and Paul Ricard's resurfaced circuits seems to suggest the decision was taken having assessed the struggles teams encountered during pre-season.
Maurice Hamilton: Not deliberately! The combination of track temperature, track surface and the thinner gauge rubber happened to suit Mercedes better than Ferrari on the day. With competitiveness throughout the grid being as intense as it is, it's the little details that make the difference. It will probably be a completely different story (hopefully) at Monaco.
Kate Walker: No. There were reports of inconsistencies between the tyre dimensions provided for wind tunnel testing and those given to the teams at the post-season test last year, and according to the rumour mill, several teams have been struggling because they hedged their bets on the wrong version of the rubber. The situation is said to have been worse at the back of the grid, and partly behind Williams' struggles, so I'm going to place my faith in Pirelli's changes having been made for the greater good of the sport, and in the interest of fairer competition throughout the grid, than something having been done to advantage or disadvantage any one team.
Laurence Edmondson: Sebastian Vettel tested the 'normal' thicker tread tyres on Tuesday and, guess what, his rear tyres came back horribly blistered. OK, the issue may have been worse on the Mercedes, but there's no doubt Pirelli brought the most suitable tyre for the event. The story was blown out of proportion during the weekend, but beneath it all is the simple fact that Mercedes had the quicker car in Spain.
What should Toro Rosso do about Brendon Hartley?
NS: It's hard to see him staying in the car much longer. As good a story as it was, and as talented as Hartley clearly is, the New Zealander has never seemed like a long-term project for Helmut Marko. Red Bull has no ready-made talents ready to step up from its driver programme currently but, with rumours swirling of Pascal Wehrlein and a recent visit to Red Bull's headquarters in Austria, there are clearly options open to the team to give this team the performance lift it needs.
MH: He made a small mistake at a big cost on Saturday but hung in there in the race and did a good job considering he was suffering the after-effects of the shunt. Looking at this and the Baku misjudgement that nearly took out both Toro Rosso drivers, the easy option is to say he's had his chance. I think Toro Rosso should stick with him -- for the moment.
KW: Sad to say, but Brendon's not really done the best job of acquitting himself thus far. There have been bits of human error, and bits of bad luck, but the resultant lack of points is the sort of thing the Red Bull family frowns upon. We can't forget the quick dismissal of Daniil Kvyat after some patchy performances and just one race after his Shanghai podium -- Hartley is certainly under threat. As for a replacement, there's chatter of Pascal Wehrlein, but longer term Honda are said to be keen to see a Japanese driver in the car -- F2 drivers Tadasuke Makino and Nirei Fukuzumi are both Honda-backed, but need superlicenses.
LE: We all know how ruthless the Red Bull driver programme can be, but I think it would be a mistake to drop him so early in his first full season in F1. In Australia he had a lock up at Turn 1 and a puncture later in the race, but the Toro Rosso wasn't very competitive there anyway. In Bahrain he hit a bird in qualifying, which hampered his progress on a weekend when the car clearly was very quick. In China a miscommunication resulted in a collision with his teammate and in Baku he had a puncture in qualifying before going from 19th on the grid to 10th in the race. Yes, the Spain shunt was costly, but he certainly deserves more chances.
Barcelona's race is up for renewal after 2019. Does it deserve to stay on the calendar?
NS: As a test venue, certainly. It's easy and relatively cheap for teams to get to during pre-season. In terms of the race, I've been scratching my head over this question for a while. As someone born two years before the first race at the Circuit de Catalunya, I can't imagine an F1 calendar without it and think it just about qualifies as one of the "historic" circuits Liberty Media has promised to protect.
MH: Having been to every GP here since the first in 1991, I'm in two minds about this. The layout has a bit of everything. But the racing is never great because of the limitation on overtaking and they took some of the excitement away when adding the final chicane in 2007. If there are viable new alternatives and the calendar is crowded, I wouldn't lose any sleep over Barcelona being dropped.
KW: No. No, no, no. The facility is decaying, and it wasn't all that great in the first place. Everyone in F1 knows it like the back of their hands, because we spend nearly four weeks a year at the track, what with racing and testing. And that's nothing compared to the bad old days of in-season testing, when the circus practically lived at the Circuit de Catalunya. It doesn't offer the most thrilling of races, there are all manner of issues related to theft and damages, and this year we didn't even get good weather! In my dreams, the Spanish GP would be at Montjuic or Jarama.
LE: Over 120,000 fans attended the three days of the Spanish Grand Prix, so it would be a shame to remove a race that still has such strong support. Changes to regulations for 2019 will increase the overtaking power of the DRS, so I'd like to see how the racing is next year before making a decision.
Has Romain Grosjean reverted to his erratic days of 2012?
NS: I don't think it's quite that bad. Sunday's mistake was made worse by the fact he ended up in the middle of the track (with his foot firmly down on the pedal). Clearly, Grosjean is driving with frustration, both from the stellar form of Kevin Magnussen and his own failure to score any points. Give him a good result or two and I think we'll have the "new" Grosjean of the last few years back in no time.
MH: Having made such a strong and impressive recovery from the controversy of 2012, it's hard to believe he's allowed this to happen. But it's difficult to come to any other conclusion, particularly following the last two incidents in Baku and Barcelona. Kevin Magnussen's rise in form seems to have got to Grosjean and now he's overdriving and thinking too much. Monaco is going to be a big test.
KW: Poor RoGro. Whatever's going on, it's not his year. Three retirements in five races is not a statistic anyone wants to see, let alone a driver currently in their seventh full season in the sport... The Australian disaster was nothing to do with him, and cost Romain (and Kevin!) a likely strong points finish. Baku, on the other hand, was driver error under the Safety Car, a self-inflicted shunt that probably still makes him cringe. And then there was yesterday, a first lap incident for which Grosjean was blamed and penalised, putting him on an automatic back foot in Monaco. I think it's cruel to blame everything on his formerly erratic style, but it's fair to say Romain's not been on it this year -- my hunch is that K-Mag has gotten in his head.
LE: By his own admission, Grosjean is an emotionally fragile driver. After 2012 he did the right thing and sought out a sports psychologist following his series of accidents, who he continues to consult to this day. When he has full confidence in himself and the car, he is one of the quickest drivers on the grid but when things aren't going well he goes into a downwards spiral. Hopefully a bit of luck in Monaco will help him overcome the grid penalty and secure his first points of the season.
Which of the top three teams will be on top in Monaco?
NS: Red Bull. The RB14 looked mighty through Spain's final sector. The team left a lot of points on the table in Azerbaijan and it should be targeting the maximum from Monte Carlo, although I think they will face a stern challenge from Ferrari. My early tip is another thrilling pole lap from Daniel Ricciardo, which he can convert into a win (assuming Red Bull has the tyres ready this time, of course).
MH: It's got to be Red Bull territory, with Ferrari ahead of Mercedes. But with so much depending on circumstances -- as mentioned in the answer to the first question -- you never know who might have the edge. I wouldn't mind betting on Daniel Ricciardo repeating the sparkling form seen with his first pole in 2016.
KW: Mathematically, probably Lewis -- his 17-point lead in the standings means he'd need to finish off the podium for a shift in the drivers' championship. When it comes to actual Sunday results, however, it's really hard to call. We saw a resurgent Mercedes this weekend, but the colder weather boosted the team's ability to get the most out of their tyres, and we also saw enough VSC action that the rubber wasn't over-stressed. If Monaco proves hot and sunny, Ferrari could well be on top again. With track position king, we'll know the likely podium by the end of qualy on Saturday, but not before.
LE: If Red Bull isn't on pole in Monaco it will represent a big failure for the team. The RB14's race pace has been very impressive when it's had clear air this year and in Monaco the power deficiency of its Renault engine should be masked by the lack of straights. Expect another tricky weekend for Mercedes as the drivers struggle to keep the front tyres up to temperature and the rears from overheating.