Except no where is it ever stated that Geostigma affects the mental state of the victim. We only see Cloud affected by hallucinations and seizures, no one else.

The Compilation Ultimania doesn't even mention mental side affects of the disease, only that it affects the immune system, causes black spots, and eventual death. Nothing about causing a supernatural mental state of mind. For all we know, Cloud's mental issues from AC could be leftovers from the Sephiroth Clone experiment. Cloud may have finally overcome the Jenova cells and Sephiroth's will but it doesn't necessarily mean he's mentally strong enough to hold back subsequent attacks.

My issue is here is from a writing standpoint. Giving Cloud an incurable disease nd shackling him down with a kid with the same disease all so you can use it as an excuse to have Cloud spend the entire movie moping around about events that were resolved in the original game ultimately retconning the original for the sake of giving Cloud something to do cause obviously he's not a good enough character to overcome anything outside of mental trauma brought on by his past just like his game. In almost every title he appears in he basically relives the plot of VII, except he gets more depressing and appears more like a sick shadow of his former self.

The Compilation has done nothing but spit on the name of the original cause at this point in time if there ever is going to be a VII remake we now have to change the original in order to have everything conform to the retcon continuity from the Compilation. Now I don't claim to be a great writer but somehow, it just seems illogical to create sequels and prequels that do not conform to the continuity of the original and instead strike out on your own and create a scenario where the original will have to be changed considerably in order to fit into the sequels/prequels that were made 10 years after the fact. That's just bad writing in my book. Especially since I don't feel either Cloud, Tifa, or Sephiroth appear in any of these titles acting the same way they did in the game.