Flat-ish is ok... Telerik's Sitefinity forums appearance is quite nice.
2. make every color customizable in user profile (nav bar / bg back etc - all fonts - colours = there is no design - it is the USERS design
Actually, you could use a stock forum CMS and have this out of the box.
3. lose the 3d 9 guy (for now) we need flat 9 guy. (for now) use the one i signed away to ms in code for fun - it is metro flat - make it available to overlay as white transparent - or black transparent - that should cover most needs
Yep, flatten him, top to bottom ...with a piano ?
4. layout - fine - keep same
No it's not. It needs work, and it needs to be responsive, to support mobile (first) access.
5. thread views: add them BACK! :P
Again, plenty of stock forum products allow users to organise views, out of the box.