I couldn't care less about bezels. I'm the type that would rather stretch some games to get them to display in full screen than toss bezels up, so that's a none issue for me.
As far as the pause screen goes, there's three things I want:
Management for save states and save state slots in a convenient manner that emulates the menus of games with native game saves to prevent accidental overwrites by other people and to make it easy and convenient for everyone to come in, sit down, and save and load their progress. Something like PPSSPP's design for save states, for example, with the date and time the save was created visible, along with a screenshot.
An option to tie save state slots to profiles to better prevent Sam from coming in and saving on top of of Steve's game
An option to easily exit the emulator/game being played.
Obviously, things like game manuals and whatnot could be added in later, but that's not important.
Another important thing to have is something that either gives people a better UI for Retroarch/core options when playing games through it, or when Retroarch is running, there's a funtion to drop right into the core menu and back out into Launchbox's pause menu. If someone wants to manage CRT filters or game cheats or whatnot mid-game, they're going to need access to Retroarch either directly or via Launchbox itself.