My thoughts on the idea of combining BL and UU as many have proposed (sorry if I'm a bit off-topic, but I read the first forty pages of this thread before the endless repetition of the same few arguements, debates, and nutty suggestions convinced me I wouldn't miss anything by skipping to the end) is that there wouldn't be any problem with it if tiering was consistent. Thing is, it isn't. It's much easier for a BL Pokemon to climb into OU as it is for it to fall into UU, but because BL is the banlist for UU and based far more on power than on usage, I'd have to say that BL is closer to a "OUs that aren't used enough to be considered OU" tier than a "UUs that were banned from OU" tier. The usage criteria just confuses things, because BL Pokemon are just as often OU-strength Pokemon that simply have had their usage minimized by specific OU threats (for example, I hear Porygon2 usage has spiked in the Suspect Test ladder) as they are arbitrarily-banned Pokemon that would be top-tier UU if moved down, and in terms of power there's a definite and more or less constant slope from the top to the bottom, with no obvious places to draw the "OU" and "UU" lines.
Yes, I know that power isn't supposed to be a major consideration in tiers, but there's no avoiding the fact that it is, since usage is largely determined by power (the best are used the most and therefore become OU) and UU bans stuff based on power. I think the revamp supporters think that testing all the BLs would make things less arbitrary and more natural, rather than the current metagame which was produced by a bunch of theorymonning.
That's a flawed assumption, though, because what it comes down to is that the instant we acknowledge the need to have a UU banlist beyond "no OUs, no non-unique NFEs" we're drawing a random, arbitrary line in the sand beyond which things are too strong for our desired UU, and retesting everything at once doesn't do anything but move the line. It doesn't fundamentally change the way the metagame is produced or make things more "correct", it just means the new UU will overlap more with OU and be less distinct because of that - which many find undesirable. To have a true, natural, usage-based UU means throwing balance out the window, and the very act of attempting to produce a balanced UU metagame means that it's no longer merely a tier of UnderUsed Pokemon but rather a tier that is merely named "UU" and only contains critters that aren't OU and are weaker than X, where X is the line between UU and BL. Pokemon that can't function in the OU metagame but are too strong for the UU metagame are likewise a natural byproduct of having a UU metagame.
I haven't even seen any Steelix or Weezing yet, given the newness of the changes and the fact that I've been mostly playing UU with the recent Smogon Tour in mind, and I'm already struck by how much more defensive the UU metagame is compared to OU. I can't see Weezing and Steelix improving that.
Given all the talk about BL's creation being "flawed" and therefore it needs to be started all over from scratch...Red and Blue were quite flawed, yet I didn't see any complaining when Nintendo merely improved on them for later games rather than gutting the entire system and redoing it from scratch.