I wasn’t active in the old forums, but I did poke around a bit. I don’t think it’s too bad and I think your reasons are all very just. If I were you, I would have done the same thing. In my own experience of running a site and a forum on the side, I found them being completely separate from each other was a hassle for exactly the reasons you stated. So I can’t really blame you!
Anyway, lookin’ good! Keep up the great work, Koichi!