Personally, I would prefer the UI just have improved contrast in Tesla's skin choices. For me, that would make a great difference, especially during the day with the grey MS interface we now have. IIRC from early UI work I was involved with years ago, colors & contrast can have a significant impact on how rapidly and easily visible something is. Increased text size is another option. As you may suspect, there are tradeoffs between all three things -- especially trying to ensure the interface is as usable by people that may not be able to see certain colors. We almost never used colors alone to differentiate status, for that reason, and always tried to change wording or graphics at the same time to prevent our needing to maintain multiple interfaces to cover all our bases.
FWIW, I have worn bifocals for years, purposely so I can more easily read details on my PC/Mac workstations and the Nav of my former vehicles (Lexus, MBZ, & BMW). I also have a pair of bifocal sunglasses for use in my vehicles. My MS isn't that much worse than I remember from my previous vehicles, nor does it use any more small text from what I remember -- but as I said before, this grey skin Tesla has implemented in v7.0 may be a large part of the challenge. I for example, don't have as much of an issue viewing the Tesla "night time" interface, even during the day, where text sizes seem to be the same, but color/contrast are quite different.