I really like it when robot troops have human elements to them. I think the whole idea of making human shaped robots, but having them not be human, is counter-productive. If you want a robot with integral weaponry, why not just make a tank shaped robot? On the other hand a robot that can use any weapon available makes sense to me. It may not be realistic, but do we really want realistic science fiction? I don't. That's why I like Star Wars and Doctor Who and G.I. Joe.
It depends on your canon to be honest, I always see these are not terminators, who would not be sneaking around in dynamic poses, if these are your trade federation bots then yup see where you're going. Re integrated weapons, my point, rather clumsily made, was I don't 'buy' the flamer backpack (as none of the original figs with flame units had those backpacks) but would go for a flamer with an integrated fuel canister.
I also do like the idea of some level of integration of weapons, but also appreciate the flexibility that comes with being programmed to shoot anything at anyone!

Cheers