I'm curious as to what others are thinking about the Assemblies so far.
First: Speedloader Pistols are really, really good. They solve the major problem of a Marksman build, and thanks to the Chained Court change and the starting AoM mod (reset for Technical), they're very easy to assemble. I think the Speedloader is better than any other Pistol Assembly, Exotic, or Unique, with the singular exception of the Blaster (which does the same thing, just better); its speed advantage is just too much for the others to supplant. (Though I'll never say no to the Jackal, because the ability to break walls with a pistol is godly. The Blaster and Energy Pistol do that too though, I think...) It's good enough that I'd consider going for two even if you needed Whizkid, since I don't run MGK.
Second: Power Armor is the best armor in the game. Anything that could be better is much harder to assemble, requiring multiple Uniques and Whizkid and resulting in something with less move speed and knockback resistance. (See: Nanofiber Skin Cybernetic. Nanofiber is just terrible in general.) The problem is, it's so good, there's no real reason to use the Nano Pack on anything else, and a good number of assemblies require it.
Third: Tactical Armor and Boots are probably tied at my second favorite Assembly (after the Speedloader). Not having to carry any Green or Blue Armor is really nice for inventory space, and the Tactical Boots are the best footwear thanks to their move speed and knockback resist. (Phaseshift is a little slower and it adds to knockback, so it's not worth it unless you find the armor too.) The new Chained Court also means you can get one of them guaranteed on every run if you want it.
Fourth: When would you actually use High Power Weapon as it stands? You might if you're running Ammochain, but I don't think you can add Agility Mods to a High Power Weapon even with Whizkid, so accuracy is a problem even if reloading isn't. Most builds don't run Reloader unless you're running Shottyman, but Shotguns can't be modded with High Power and neither can Rocket Launchers, so Fireangel can't use it, either. (I'm pretty sure you CAN mod a Missile Launcher to be High Power, which seems like more reason to go to the Wall in such runs. Add a Bulk first and it's a three-shot 6d8, which is a fair trade.) You could put it on a BFG, I guess. I think you should be able to use it with the Combat Shotgun, though; yes, it might be a bit of an automatic inclusion in builds with Shottyman, but looking at the above items, I'm guessing that isn't why it was excluded.
The mechanic is really good, if a little inconsistent in the power levels. I'm looking forward to reading about the Master assemblies whenever the recipes are found!