I wouldn't say it like that way. But yeah, back in time there was a news piece where Oda explained his editor or some anime stuff worker (I'm not sure about the details) as to why Weevil is a very cool character. The worker was surprised and asked Oda what makes Weevil cool, and Oda explained him, after which he agreed.
Now, knowing Oda he wouldn't call Weevil cool if he's a bad guy, plus Weevil is being manipulated by his mother, Weevil in reality just wants to avenge his father's death, but Bakin is against it since she only wants money, but Weevil is not interested in money. Luffy is infamous for inviting weird people to his crew (that's how Brook joined) so if by some chance something would happen to Bakin and Weevil was free to do whatever he wants, then he would try to kill Blackbeard. And since Luffy is destined to take him out–and he will probably say so to Weevil–them Weevil joining Luffy makes sense. On top of that, Weevil and Luffy are very similar, they are both retarded, so I assume they would become best friends.
But there's another reason: after the abolishment of the Shichinukai system, the ex–Shichinukais are now joining the Emperors. Jinbe joined Luffy, Crocodile and Mihawk are part of Buggy's crew. It would make whole a lot more sense if Weevil joined Luffy. I assume that Doflamingo will eventually escape and join one of the Emperors as well, ether Blackbeard or Buggy.