I´ven been playing this game multiple times now, and I´ve started to think about this Materia System -
I actually think it´s a little TOO powerful at times.
I mean, here you´re able to build your characters insanily powerful, so that just about everything gets blown to smithereens without you even having to do anything at all, and even sometimes gain something out of it!
Seriously, not long ago I beat SEPHIROTH HIMSELF by just summoning two "Knights of Round" using the W-Summon command, and there are lots of moments similar to that one!
This is a combo example:
Ultima--Sneak Attack, Ultima--Quadra Magic, Ultima--MP Turbo, Ultima--HP Aborb
Ultima--MP Absorb, Ultima--Magic Counter, Ultima--Steal As Well, Phoenix--Final Attack
This is one of the most crazy combos I can think of, and it´s almost too much.
Sure, it DOES get very fun considering all your struggles to get there, but I still think you get a little too many Materia Slots.