Like hell he does. Personally, I rarely approve “lone wolf” characters without an OOC understanding that they’re going to learn to work with and trust the rest of the party, for exactly this reason. But even if you do, there’s no reason you need to continue to give in to his requests if it’s getting in the way of the rest of the group’s play.

The thing is, that’s a disruptive behavior. You might need to watch for a while to determine whether it’s honest enthusiasm getting out of hand or intentional spotlight hogging, but either way, you’re going to need to have a discussion with that player at some point and make him understand that his character won’t be allowed to dominate every game session.

If the player’s utterly unwilling to compromise on the character’s behavior, citing roleplaying, then kindly offer to collaborate on a good way to write that character out of the game in the next session or so and introduce the player’s new, more team-oriented character, which he will roll up before then. This is a bit heavy-handed, admittedly, but when you’re balancing the enjoyment of four other people against the enjoyment of your lone wolf’s player…

Having specialised characters that usually act solo like the cat-burglar inflitrator, the behind-the-scene hacker and the positioned sniper was something that I encouraged in my d20 Modern campaign but it did become quite a problem in game. Which in the end I decided that those characters had to be on the field to overcome those obstacles directly (like the hacker actually had to be accessing the computer in the villain’s lab rather than from a hacking station somewhere miles away).

Party splits can never happen too often if you have the dreaded lone wolf type character which one of my players prominently plays. He would request for solo session after solo session during the game and sometimes it is something that the DM has to oblige because it’s in his background.

I agree that having draconian rules against party splits really isn’t the way to go but having a clearly stated and laid out policy if a party split happens and repeatedly discouraging it is a good start.

Personally, I’m not a big fan of party splits and I would normally ask my players to reconsider when they go for that direction. Not only because is it bad tactically but also ruins the fun for the other players.