The armor is comparable to TT, and has a very good reason why it provides the same armor points at a lighter weight instead of increased armor at the same weight. (bulkier yet lighter design, not lighter design with the same bulk, you don't want your Raven to look like the Stay Puft Marshmallow Man do you?)
Community designed Mechs are a good way to permanently break all game balance if they don't have to go through PGI first. In addition, in Lore, it takes a rather large manufacturing facility to make anything except the Urbie, and no Pirate, Merc, or simple Loyalist would ever 'own' one of those for more than a few seconds.
The different parts, apart from the structure-based stuff on Battlemechs, and mandatory locked equipment on the Omnimech sections, sound like a good idea to me. Compact cockpit, (could have reduced visibility through the glass, and a reduced turn rate or some such) reinforced servos, (double the internal structure of an arm or leg) laser insulators, (overheat doesn't crit the CT, but only the weapon component itself) all are extra components from TT that would be very cool to have in this game.
No, just no. The HUD is exactly what it is supposed to be, a Heads Up Display. Forcing you to revert to pre-1950's display technology in a Mech firing lasers isn't in the slightest logical.