A servant of the Dragon and a member of the 6RNT here. Also, my alter ego is a UI/UX designer, so...
We have mechlab improvements coming soon, ladies and gentlemen. While that's great, the rest of the UI could use some improvements. Now, while a complete overhaul might not be likely, there are features that shouldn't be hard and very time consuming to implement, but will benefit the user experience a good deal.
I'll start with some basic suggestions. Please, add your comments and suggestions of your own to this thread, and let's hope PGI takes note.
Here we go:
Mechlab -> Equipping modules
The amount of modules is ever growing, and that's great, but it's getting harder to manage.
We need an additional filtering options:
- Show all - what we have now
- Upgraded - show only those you've actually invested GXP in to level up
- Owned - show only what you have in stock
- Relevant - this would be slightly more difficult to implement - show only modules that are useful on the mech as it's currently equipped

Skills -> Mech Trees
Akin to the situation with the modules, we have lots of mechs now. It would be good to be able to filter what shows by All / IS / Clan. Also, a subtle variation in the background colour behind the mech name to indicate the weight class would be a good visual aid.

Skills -> Pilot Trees
Lots of stuff to spend GXP on. Again, being able to filter by All / IS / Clan will help. A more visual representation of the upgrade level than just a number also be nice.

Mechlab - the list of mechs
Again, filter by All / IS / Clans
The triangle in the bottom right could be shaded slightly to reflect the weight-class
Now, one feature I'd absolutely love. Instead of the default images for each mech, use a thumbnail that's auto-generated from the mechlab model of the mech, showing camo and weapons that are actually on it. That alone will make it a lot easier to find the mech you need, not to mention that it'll be way cool to see.

Game Options -> Video
There have been talks about adding those to the config menu for a long time, but it keeps getting overtaken by other priorities.
We know there are options that can already be edited manually in the game files, and people are using them. Bringing these setting the in-game menu will make it fair to players who didn't know about them, not to mention more convenient for everyone.
