I was going to respond to this thread but Ryotaro already perfectly summed up my thoughts ... it saves me time
Also, yes, things like power-ups, generec posing and recycled transformations have been around since before Ishinomori's productions. That's where he got some of his ideas I suppose. Just take an old show like Mazinger Z and you'll already see lots of that.
Basically I think these are all signature moves in a lot of anime and more specifically robot anime.