I agree. In ME2 the HUD scaled properly with higher resolutions but in ME3 at 1920x1080 it's fairly unreadable. There may be a solution, but I can't say I felt that it did a lot of difference for me, and it does involve changing game files in a manner that might trigger an anticheat ban if you play online (I haven't played the multiplayer part of ME3, so I can't really say).
DISCLAIMER: This is a potentially dangerous operation that modified game files and may, if not done properly, break your game. So make sure to have a backup of the original Coalesced.ini file as it was before tampering, so you can restore the game's function if broken. If you're going to play online, always switch back to your unmodified Coalesced.ini before playing, unless you want to tempt the anticheat system.
To implement the tweak you will need Wenchy's Coalesced.ini editor and change two parameters in the section [biogame.ini > sfxgame > biohud]. The parameters are safearearatiox and safearearatioy. They default to 0.05. Changing both to 0.10 or higher (I set mine at 1.0) should double the HUD size, but it doesn't seem to go higher than double, whatever the number you enter, as long as it's at least 0.10.
The Coalesced.ini file you will need to edit (remember: backup!) is in the BIOGame\CookedPCConsole folder below whereever you installed ME3.
