After finishing Red Dead Redemption on Xenia, I have a weird itch to play some more of the open world games I've missed. I was just completely exhausted with sandbox games by around 2013 and avoided all of them, even the ones I heard good things about.
Some of the games on my "maybe check out" list:
Sleeping Dogs - Apparently a really good GTA clone. The Hong Kong setting and melee combat make it stand out.
Assassin's Creed 4 - The two additional Ezio games and Assassin's Creed 3 were big factors in why I got completely burned out on open world games but the ship combat is supposed to be really good- also pirates are cool. It should also predate the series turning into a singleplayer MMO thing.
Far Cry 3 - Never got around to playing this despite all the praise. I know the FC3 style got milked to death but there's probably a reason it became used as a template for Ubisoft games. Wasn't this also the game with the retrofuturistic 1980s DLC campaign with Michael Biehn?
Mad Max - From what I've seen this is a pretty generic open world game in the vein of the later Arkham games but it seemed like a pretty faithful recreation of the Mad Max world in video game form.
do you want to be a pirate? you get to be a pirate. the combat can get a bit easy and repetitive, but there's a large amount of upgrading that can be done to the ship. it can be a pretty fun gameplay loop.