It will be nearly impossible to determine the top driver but someone may really dive into the analytics and make a great case.
Senna was cut short....it would have been so much better to see him and Schu head to head for a few more years. Schu was ridiculously good at hitting key laps at key times. Vettel has been a phenomenal front runner.
I go for how cool you are in the fight and that leaves me at Senna and Lewis....Senna had to battle Prost in his own team, none of these other guys had that. Prost is just a fraction off these mega stars and maybe is right alongside them in his own right.
Until proven otherwise....i'm left with Senna even though he was not perfect either. Hitting Nakajima in Brazil, putting it in the wall at Monaco and taking out Prost in Japan.
Really great debate...Lewis is still piling on and may end up as the greatest of all time.
Worth noting on Senna's case; yes, his career was cut short, but what options would he have had for the remaining years? Frank Williams was notorious for lowballing proven drivers, so I don't think that relationship would've lasted for more than two years. Say Senna (who's btw 36 at this point after the season opener) was looking for a seat in 1996, what realistic options would he have? For him to even consider it, the team would have to be competitive and without a number 1 who can veto the move.
(Williams is not in the conversation, because I'm assuming Frank has refused to pay up)
Ferrari, nope, Schumacher would veto that and I doubt Senna would want to play second fiddle to him anyway.
Benetton, I mean they still finished on the podium, but the writing was on the wall as soon as MSC left and took some technical staff along with him as well. Senna wasn't stupid.
McLaren, they were still rebuilding. The relationship is there, but the car wasn't competitive.
The rest aren't even worth mentioning. I really think Senna would've retired after '95, championship or not in those two years with Williams.