I don't think the game feels empty, but there are a lot of servers which I think is essentially to account for the game's engine. Too many people in one place and performance really takes a hit so they tried to address that somewhat by reducing average population density, lesser of two evils and all.
Orange bracers and belts are mostly crafted only but can be found as rare drops. Orange 'main' slots (chest/legs/boots/gloves/head) are all pretty widely available from quests, commendation vendors, pvp and crafting. One exception is an orange belt is pretty easily purchased from the fleet (space mission) commendation vendor.
Really for endgame there's not much of a difference between all the professions now. The other professions are just as good as biochem since the change to rakata stims as long as you don't mind paying for the blue level 48 stims since the stats they provide are now the same. Technically buying 'exotech' stims is the "best" but I think it's going to be a while before they're more widely available, even then it's a pretty minor boost at best.
Grenades are actually pretty interesting, I've levelled Cybertech to 400 on an alt but haven't played with them yet. Mostly just using it to keep alt's gear up to date via mods/armorings; I quite like it really.
How they handle orange gear with augments and how it will interact with the eventual change to 'unbind' high level armorings (and set bonuses) from PVP and PVE gear remains to be seen. On one hand it could result in crafting becoming the -only- source of endgame gear and demand for augments skyrocketing; on the other I feel like they wouldn't want tier gear to simply become 'mod fodder' and then be cast aside so quickly.