Just my .02 C here, but in some ways advancing technology and advanced, more complex devices make things easier for the end user, not harder.
For an example, may I point out the difference between the standard infantry weapon circa 1800 and standard infantry weapon circa 2000?
Ask yourself which is more complex, a flintlock or an AK-47? Ok, no brainer there.
Now, ask yourself which is easier for the soldier to use effectively? I'll admit that when a Kalashnikov jams, which happens about once in a blue moon, it can be a little tricky to clear, but asides from that isn't the assault rifle much easier to use than a flintlock? I had to research the procedure for using a flintlock for a product I wrote once and man, it was a process to load one of those bedamned things for one shot.
Now, how hard it it to reload an AK? Not nearly as hard.
Sure, the Ak is vastly more complex than the flintlock and requires a vastly higher tech/industrial base to support it, true. But in the end it's much easier for a soldier to use an AK than a flintlock.
So, maybe powerarmor will be similar. Complex, yes. Likely far more so than any fighter jet today, but in the end possibly easier for the soldier to use.
More complex doesn't mean harder to use or learn to use. A lot of modern computers are more complex than those poor dinosaurs from the early 80's, for easier to learn and use.