I get what you are trying to say Foster, but I'm a bit confused as to the sources you chose to quote,
The latest military-grade frames are powered by a reciprocating internal combustion engine. It is located in a backpack-like housing unit on the rear of the machine. At its core is a large, V-shaped support axle, to which multi-chamber cylindrical engine blocks are mounted. The cylinders are arranged parallel to each other. The pistons rotate around the support axle as the engine runs.
Once again, not to be a douche, but this is an engine. That's all.
Each engine block’s output shaft is connected to an assembly housing an axial piston pump, an electric generator and an axial-flow fan. This lets it run on both hydraulic pressure and electrical energy.
This I would assume is the core of your argument, and much more helpful. To start, electrical motors are highly favorable for rapid acceleration, and deceleration, but terrible at maintaining speeds, it's why many hybrids will use electricity during acceleration, then switch to gas power while maintaining a relatively constant speed (This also permits recharging of the battery during operation) The downfall to electric motors is generally their lack of actual power (Torque for you non-layman) if you want to see this in action, stick your hand into a fan (this may be a bad idea depending on the kind and design of fan) It's spinning ridiculously fast, but I can stop mine with a pinky, and only.
Hydraulics on the other hand, generate ridcuously high amounts of power (if a fan was run off hydraulics, it wouldn't be good at keeping you cool, but if you your hand in, and it got stuck, you better hope the fan's blade is made out of some real shit material) at low speeds. It's also very reliable when it comes to power transmission (smooth movements) provided a leak isn't sprung.
Properly combined, these two systems would be rather reliable for smooth, graceful movements.
For rapid twitch like movements (What I assume you meant) much less so