Is power armor a vidya joke or does it actually have potential?

Are you the same gook who advocated for the use of “power swords”?

Yes, why not?

Oh yeah, you are entirely correct there. Until powered armour is as cheap as modern kevlar it will be impossible or maybe just retarded. You might be able to use it as specialist kit for very carefully chosen and trained units in about 50 years, but until then it's just a sci-fi fantasy. I do rather enjoy indulging n sci-fi fantasies though. Although when it gets to the point I described in there's not much point in leaving the human in the system (with any luck by then the senior staff officers will have cooled the fuck down when it comes to automation in warfare).

A human shaped tank that can fit through doorways, climb stairs, etc. Something a tank shaped tank can't really do. And of course, tanks are (more or less)limited to fixed weaponry, whereas a dude in power armor can just put down whatever he's carrying and pick up something else.

Power armor isn't replacement for tanks, it's replacement for special forces infantry. At least, assuming suitable power sources can be developed.

Won't happen until batteries get small enough. Wearing massive steel plates won't happen any time soon, but polymers are only getting more advanced by the day and plastic armor has a lot of potential.

You don't need an AT rifle to penetrate any kind of armor a person could wear.

Modern full body armor is 20lb, and it leaves about 60% of the body unprotected. Any kind of full protection would weigh 50lb, plus equipment and uniform being around 30lb, and pack being 50lb. Meaning a powered suit is still going to offer protection against 7.62AP at best. At which point enemy just goes up a caliber, any kind of normal sniper or general purpose machine gun would have a decent chance of going through.

And that's not even taking about frag grenades, rifle grenades or underbarrel HEAT shells that are available readily everywhere, or shit like flechettes which go clean through armor and don't weigh any more than regular rounds.

Using this powered suit to carry armor is retarded.

Nigger are you serious? The thermobaric warhead would turn the wearer into marmelade.

What would be the validity of using magnetically powered joints for power armour?

Servos are far too unwieldy for this kind of work and are prone to damage, so what if you had a series of magnets form the joints? As an added bonus it might be possible they could become their own dynamos, although I don't know if that would be viable.

But what if we made a tank shaped human?

Why do you think the American diet is what it is? America is always ahead of (and growing out) the curve.