The actual HUD, the style feels wrong, I thought it was just the color which would be easily fixable but it's clearly not
I think it might look too...modern?

It lacks a professional look. The Hud looks like someone took ms paint and just drew bright green lines over the screen. Fallout 3's had a more natural look like it was meant to be that way and fit. This hud and ui on the other hand looks too barebones and simplistic I guess, it doesn't really seem to mesh though.

Like the hud in panzer general is pretty simplistic, but it seems to blend well with the rest of the game.
"but you can just mod it to make it-"
stop
In my opinion modders should only be expected to add on to a game. Having other people fix your bad design or mistakes you are too lazy to fix is a really bad on a companies part and sets a very low standard.