I would play this game more if it weren't so slow. The interstitial scenes - loading battles, changing rounds - are annoying, as are unskippable events and the 35 minute intro. The slow movement rate and AI decision-making is too.
Unfortunately, we haven't dabbled in events much yet. The AI has been improved in GG, but out of all the things you listed, that's about all we've really touched so far.
By improved you mean faster, less stupid, or both?
Less stupid. You see, in Vanilla FFTA, each skill has an AI value- basically, how important the skill is to the AI. Skills like Thunder had higher AI Value than skills like Thundaga, meaning they would purposely use less potent skills more often. FFTA GG removes those limits and improves general AI behavior, although it still has its stupid moments.