Downside - The plot once you start reading between the lines. One of the reason why people play video games is to get away from real life BS/political issues. . .the developers kind of forgot that little fact. . . The main cast(heroes) sometimes come off as very self-serving(except for Red XIII) and worse keeping things from Cloud(Main Character) that in hind sight they shouldn't have. I consider Cid in the original to be the worse Cid in the whole series. He was fouled mouth to the point of being verbally abusive. Hopefully they will clean him a little bit along with Barrett in terms of language.
Overall the original VII is best for all the stuff that can be done in terms of exploration and character stat building. Plot wise, it depends on how you feel about certain real life political issues.
Getting away from real life BS and political shit doesn't mean characters can't be self serving. I'm not sure where you were going with that one. You say "politics" several times but never actually state what the political problems with the game are. Because characters being dicks or having their own goals doesn't seem like the way to say "we want to get away from life's issues" when I really have no problem playing around in some fantasy world that has it's own issues. So long as they're colored enough by it's own setting that it's obvious it's a conflict *in this setting* and not a poor excuse to harp on about current events.