>>37351054PMD is a better narrative experience. It has a story that, while not deep, carries a serious emotional weight unlike anything in the core games. I think what PMD does best is create an atmosphere that's easy to immerse yourself in because at its core it's a comfy adventure set to beautiful music.
Gates has a pretty great story and there's some argument over whether it's actually better than Explorer's. The jury's out on that, but it's definitely better from a writing standpoint. Notably, the guild is replaced by a smaller cast of secondary characters that have much more relevance and development than the guild members ever did.
Difficulty wise, the game is really easy, especially for you since you chose the best MC. Dual Chop is broken.
GTI's big disappointment is its non-existent post game content. With RT and Explorers, the game isn't nearly over when the credits roll, but GTI hardly gives you any reason to keep going beyond a single post-game event. Not to mention the lack of pokemon variety makes trying to collect 'em all pretty much pointless.