I agree he can sometimes be "hot headed", but isn't that exactly what everybody has been asking for during the losing streak? He's not like Hartnell, who can get a little "out of control" or let his emotions affect his game. An "intense" Dubi is probably the best Dubi. Just make sure he's rolled tight. Jenner and Foligno are also quite intense as well but I can see them being TOO NICE for true captain responsibilities. I get what you're saying but personally I don't see it as a negative at all.
Like the latest streak, sometimes you NEED a Dubi to burn out the room when things aren't going well. Again, isn't a "spark" the exact thing this team has needed the last month or so? Like you say he IS our leader anyway, so any awkward situation will still happen, letter or not. But really, what type of situation are you even hinting at? Dubi seems like a pretty good leader/lead by example type guy. If there's anybody that butts heads with Dubi because of the type of leader/captain he is, I'd like to see that person shipped out asap.
Overall its really not THAT big of a deal, to me or the team. But I have to say it prolly DOES bother him a little bit. I just don't see the advantage in giving it to Boone or Nick over Dubi.