I have no doubt the 1M has a fine engine and the next M3 probably will too. Large N/A engines will soon become a thing of the past on mainstream cars and we will all have to accept that. I am sure when the next M3 does appear it will be well recieved and I would love one, but right now I love my current M3.
Anyway, I have to say on looks alone I simply could not live with a 1M. It is short and stubby and does not appeal to me at all. Obviously this is a subjective view but that is what opinions are....