If anything they should allow Armstech something unique to use on their weapons that is tier geared. For example, Armormechs can craft Rakata bracers and waists. Could Armstech maybe get some Rakata tier barrel schematics at least? I wouldn't mind the idea of "batteries" for weapons, but they should be like stims and adrenals where the blue tier ones are usable by those with the designated skill level.

That's how it typically is, however, all of the end-game schematics I have seen are BoP. Even more, the materials used to craft these items are BoP as well. The higher level items (above Tionese) are BoE sometimes so you can craft them for others, but some of the key materials for the craft are still BoP. The reason for this (most likely) is that the crafting system is casual enough in this game where anyone can craft and raid efficiently at the same time.

Maybe you should take up Slicing and become super rich instantly because that's what it is for.

As stated above, Slicing is needed for higher level schematics and augments. The Mission Discoveries you can get from it are also very nice too.