I'd just like to follow up again, after playing with said poor eyesighted friend for a while last night. The largest persistent issue is the chat box. While a lot of the hud is horribly hard to read, over time a player learns what things do and it's less of a big deal.

By far the most important things to make larger are:

1) Chat text
2) Team pointers and text
3) Names above selection box (like when you aim at another player).

The main hud itself is likely quite a bit of work to fix font size wise, but I would think that these three things wouldn't be too horribly hard.