Anyway to set it to the blue Fed UI?

No i don't think so..

It's why I dont play KDF...and that's the only reason, colour shouldn't matter but it does in STO...
I think the ships are cool and if I could change the colour I would start a KDF char...
On the other hand it saves me a lot of money.

this was a big part of me leaving KDF. it is just so annoying.

I understand that Klingons are agressive so the UI should be agressive, but this makes me agressive which makes me a better klingon player, however I do not enjoy it, which comes before that

This is part of why I don't play my Klingon anymore. I'm shadeblind and the red UI is really tough to read. Also for some reason they also made enemy targets yellow or orange...I don't know which color they are since I can't see it well lol. Anyway, those colors are way too close on the spectrum to red for me to be able to tell them apart. Makes it nasty to try to tell who's an ally and who's an enemy. They actually had it the nice fed blue back in beta and then changed it to the junk they have now. I left them a a nice post back on the beta boards detailing the problems with it as well as solutions, but as you can see, I was ignored. As such, I support any changes to the Klingon UI.

You know, I've gotten used to the colors somewhat, but I still really wish it were possible to customize colors to some extent. It's the 21st century...you can customize chat text colors, why not the HUD? Seems like a simple enough thing.

Yes.. If they had it before? How hard is it to at least get to choose colour?

This is ONE of many things that IMO is easy to correct but getting totally ignored.
I love the game but all these "small" things are starting to bug me..
Couple of "small" things that bugs ME:
Space: Entering/exiting in the wrong direction, pointing where you came from?
Exiting starbases, you get put IN the starbase and starting to flicker and going back and forth (Ship: Odd) why not spawn beside the starbase?

Ground: My team are literally in/up my a'ss, some distance would be nice (ever heard of personal space?)

These things are in my opinion easy to resolve, but what do I know
Could write many more but im getting pretty mad (remiding me of all small things)about now so Im stopping.

I would also love to be able to choose the color of the HUD and the letters.

Sort of humour: If I can;t have my remove font color option here in the forums.....