I don't think my eyes are that bad, but I'm spending a lot of time squinting at UI elements, especially text.
Some sort of UI zoom would be great. I think this would essentially scale the UI as though I was running at a lower resolution.
As a fallback, better lower-resolution support would be nice. Full screen at a lower resolution forces my monitor to change resolutions, which causing a black screen for several seconds when I start the game, when I exit, and whenever I alt-tab out and back in. That's pretty annoying. I think you can potentially render at the lower resolution into a texture, then render that texture full screen at my monitor's real native resolution, providing the benefits of larger UI, the speed boost of fewer pixels to render, and not switching my monitor's resolution.
I'm only 45 minutes or so in, but I'm having a lot of fun. I look forward to some quality-of-life improvements!