You're right I would just add :

Inability to delegate. A bad technical leader think that as he can do it better, he should do it.
This prevent him from doing his jobs (make his TEAM produce better) beccause he will have less time to transmit his knowledge, plan/coordonates things...
The worst effect to this behaviour is to my mind that the coders feel under-estimated (and in a sense it's the case) and this tend to act on their mood and so on their productivity...

NOTE : I just like to precise what I said earlier, I don't think that technical manager are better, I say that I met more tech-manager in the good managers group than non-tech ones.
Of course a good tech guy won't automatically make a good manager, but I still do believe that it will be even harder for a non tech one, and I guess that you all know why (haven't you deal with commercial manager ? Financial one ? ;-)

"Only Bad Coders Badly Code In Perl" (OBC2IP)