Might get some hate for this, but as someone with zero attachment to the R78(due to being 21 years old), I don't really feel like Amazing Red Warrior is all that great of a Gunpla.

It's blocky shaped with seemingly minimal pieces, and is primarily colored in only a single shade of red, it seems to be contradicting the concept of GBF that "the more skilled the builder(ie. able to make more complicated Gunpla), the stronger potentials the Gunpla will have in Gunpla battles".

I feel like it could've at least been made more "complex" while keeping this same shape like post #1789737 for example

Why not. It is a very simple design, I'll say... Throw in some superfluous wings or swords and it will be as lost as the "strike freedom gundam", so I really cannot speak to any improvements, per se.