Regarding width, it's probably important to consider the design goals of the tent first and foremost.
There are plenty of big, unstable, heavy tents out there.
If adding width would make your tents even moderately less stable and moderately heavier, then I think they have a bit less of a reason to exist in the marketplace.
I say this all rather hesitantly, because I like a bit of extra room, too. Especially with another person.
If they would still be lighter than just about anything else and still stable "enough" in particularily terrible conditions (which is really the goal of the tents, right?) then maybe it is worth considering at least a bit of a compromise. I'm not sure.
But the stability is a very important point in consideration.
To me, the solution that makes the most sense is for the summer tent to perhaps be a bit larger, but the winter tent your normal 42" or thereabouts. In the winter survivability trumps everything, and weight just below that. In the summer skin-out weights are significantly lighter anyway, so a few more grams on a larger tent could make sense.