Servitor, those lil robots you guys used for construction, perfectly possible to fit part of one into a tool suite.
Carl could barely lift and throw them, and he has both above-average strength and an exoskeleton. I don't think you could get a little tail to hold one, certainly not without you falling over backwards.
Does it matter if they are needed? Armor and guns aren't technically needed.
...Yes. Yes they are.
And see below for the rest of the answer.
Do they need to be the best design for the tools? We use plenty of things that are ineptly designed (phone touchscreen typing for example) the idea behind them is a hands free integrated sensor and tool suite, they don't need to be the best design.
The "hands-free integrated sensor and tool suite" is why they are the best design.
And yes, it does need to be the best design. IRL, you're not going to see anyone wasting money for no reason...and the military puts precisely zero emphasis on aesthetics, or really much except efficiency, effectiveness, and ethics.