So, on Smoker's Wiki Page, it talks about the similarities between Smoker and Garp and that he'll be the Garp for Luffy. Here are the examples:
-He's a Vice Admiral (although he could be promoted).
-He supposedly has strong Haki (don't know, haven't seen him in action after the timeskip)
-He nearly arrests Luffy multiple times but Luffy always gets away
-He's doesn't follow the "Absolute Justice" code
So, what does that mean for the future. Well, I think Smoker will be among the Marines who get to Raftel and try to stop BB and Luffy, and will be the closest to do, so. If the One Piece's Poneglyph or whatever it is that people say causes the Big War at the end of the series, is bad, he might be favorable to Luffy... so if Luffy gets a kid or an heir in general, Smoker might be like his silent guardian or whatever, like Garp was with Ace.