I haven't bothered to post, ever. I had to make an account here just to discuss this when I heard about it, actually. But being a decent (1800+) Ubers player who runs very unorthodox teams, I have to say that while it's very fun using wobbufett and gastrodon and other non-ubers who have gimmicky niches, it doesn't get you very far. With that in mind, I'd support lifting some clauses because they won't be too hard on experienced players.
Looking at OHKO moves:
30% accuracy. Is it worth a moveslot to have a last-ditch maybe-successful KO? Is it worth building a team around to try and raise the accuracy when Dragon tail and Roar are on every team? Probably not. Let the OHKO's come back. They may cause some frustrating losses, but nothing big.
As for Evasion:
Prankster thundurus has been mentioned before, and that would be a terror with Double Team. It resists aura sphere and can eliminate Kyogre, meaning 100% accurate Thunder isn't guaranteed. Then there's all the other prankster users, which are annoying enough as is. No guard is on Machamp. Machamp is not viable in Ubers.
Moving to Moody:
Moody is just stupid. Sure, it's not an instant win, it can be beaten, (outside of Smeargle) but really? Octillery with one evasion boost means life just got really hard. there's already a lot of threats in Ubers to prepare for, and adding one that is very debatable and takes a lot of skill out of things isn't really fun. I will never vote for Moody.
relying on sleep talk to pick a good move? there's only a 67% chance you even do anything. insomnia isn't worth commenting on. Scarf Darkrai is beaten by other scarfers (scarf mewtwo use would go up quite a bit), and since we're discussing gimmicky things, is OHKO'd by +1 speed life orb ninjask. Breloom's too slow, but all the Chlorophyll pokemon would be really annoying. I don't really care about this one, it'd just be something new.
Species Clause? Let's face it, Arceus/Mewtwo would dominate. Neither need much team support, and can even support themselves with varying sets. Ridiculous.