I can't help but feel like there's a lot of Asgardians already.  So three possible Thors seems a bit much.  But also don't think Thor will just be cool with some punk taking his Mjolnir after Tarene already abused it.

The other notable thing, which will be in the post [@Bright_ops] posts soon, is that mjolnir is in Tony Starks personal receptionist room.  Since really the only people going there are business men who are most EASILY not worthy.  But the point is not just anyone can go there since it calls for a private elevator.