IMO, I think the best way to handle it is to delete the Tips and Tricks and the Support and Troubleshoot forum. The Tips and Tricks one is a bit too ambiguous in terms of whether something should go there or just stay in the main thread. In the same token, it also then suffers a drop in traffic because there really isn't that many tips and tricks to be discovered after a phone has been out for quite some time. The notion to delete the support forum is pretty obvious. I'd say about 80% of the threads that get moved out of the main forum are support type questions. Merge this INTO the main forum (since users don't even bother posting in the support forum anyways, might as well just make it easier for them and combine the two so there aren't redirects everywhere), and leave the Root forum (I think this is VITAL in keeping the flow of the forum as well as the stability of usage and members) as well as the Accessory forum (threads that are related to accessories can EASILY be identified whereas support/trick type threads can fall under several categories (ie. if a support question is answered, should it go to tricks? should it stay? should it be moved back now that theres a solution? should it never have been moved at all?).
If that above isn't what is available, then I'd either go with stay the same or prefixes (although as someone said, the vertical scroll on the busier forums is gonna be insane - and even worse on mobile platforms.) The suggested method I proposed above would seem to be the middle ground of keeping alot of what's working right now, but address the main gripe of users (as I said before, almost all threads moved are support-related)
Edit: Phases, do you think it would be a good idea to copy this thread into the Lounge forum as well as Android Lounge forum so that people who never scroll all the way down here can also voice their opinion (those would probably be a larger majority compared to people who check this suggestions/feedback one)?