We're obviously experiencing very different UU metagames at the moment, because besides myself I've come across very few players who use anything other the small group at the top of the tier. Its got to the point where I started leaving matches because each match is simply a rehash of the last ... I'm simply not experiencing people using stuff like Parasect and Seviper. If I play for a couple of hours I see twenty or so Ninetales, Pinsirs, Hypnos and maybe one Politoed and Seviper.
Well I never said they were used often, just that they do see occasional use, and that they have competitive potential there. I lost a match to a Seviper one time as it Giga Drained my 'counter' Gastrodon, a move I previously didn't even know it learned.
As for the current UU metagame I think there are two plausible reasons for the staleness. One is that there are so few people who play UU still that there is simply not enough regularity in play and variety of battlers to achieve a fully fleshed out metagame. People new to UU are completely overwhelmed by the depth and find the only way to get stuck in from the beginning is to copy strategies from experienced players.
Secondly, there is as yet no well defined upper boundary to help normalize the metagame besides the faux tier BL. If there were a second tier above it there would be a means of assessing growing trends in popularity of certain Pokemon that in some cases get carried forward to the tier above (I can certainly see Pinsir and Ninetales getting plenty of use up there) and therefore the tiers are less likely to get stale. No guarantee though.
The gap in quality between OU and UU is simply too great at the moment that no matter how dominating some Pokemon are in UU they will not likely ever break into OU as they are simply outclassed, therefore the only move to be made is to BL, which people are reluctant to do without good reason.
I somewhat agree with you on the state of UU. I haven't played a single match for over a month, mostly due to circumstances beyond my control, but I was already growing tired of seeing certain Pokemon again and again. Pinsir especially, and you know how much I'm against Pinsir, it simply has no grounds for being in UU. I'm very sorry if the situation has worsened still since then, but that is even more reason to press on with these changes.
On a different note, I've noticed that Hippowdon is no longer OU according to the recent statistics. I hope we can all agree that it will be an auto-BL Pokemon once a new tier is established, based purely on its trait.