I guess there is one one in every bunch as the saying goes. You really added a lot to this discussion.
As for motorcycling, I have a lot more injuries than just the new one that constricts my mobility in other areas but the knee one is an issue every day now. When I bought the Y, I thought it would give me a car that would be easier for me to enter/exit at some point. I would have never thought the 3 would be better for me. Turns out I didn't get what I thought I would with respect to ease of entry and exit with the Y and the 3 is better for me.
The point is to not make assumptions but to try the vehicle if possible. I found the Y to be less comfortable than my 3 before my injury became an issue. The specs on paper don't always tell the entire story. While the Y is vastly taller than the 3, it really doesn't translate much into headroom (0.7"). The 3 has almost an inch more legroom.
My 80 year old father in-law, who is disabled, was easily able to enter or exit the 3 or Y as another point of reference. The entry technique differs a bit though. Again I would encourage the OP, or anyone else, to try the 3 and Y a few times before making a decision. Some comparative specs below. I really think the Y could have done more with space it had internally. They gave a lot more leg room to the rear passengers but at some expense to the front passengers leg room.
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