My Opinions on the pending pokemon:
Cresselia: Never UU, Please. IMO its somewhat broken in OU. Just imagine trying to take that thing down with a UU pokemon. Especially since it has Reliable healing in UU.
Dragonite: Not UU, never. Although it is outclassed in OU it is far too good for UU
Less used rotom forms: The only reason they are not used much in OU is becuase they are outclasses by their other forms. Too good for UU
Donphan: Could be non-broken in UU but I would have to say it needs some testing
Dugtrio: UU material IMO
Alakazam:OU definetly
Rhyperior: too good for UU. Could go to BL
Umbreon: Not broken in UU, should stay in UU
Porygon2: Stays in UU, the UU metagame would be far too restricted without it
I'm not sure if you grasp how the process works. The tiering is based on usage. The top 50 or so Non-Über Pokemon make up what is OU. So recently, when the use of Donphan and Dugtrio were in decline, they weren't used enough and were made UU. Similarly, if previously UU pokemon are used enough, they get bumped up. Neither of these statistics is directly referencing the abstract power of said pokemon, just how much people use them. If something too good for UU isn't used enough in OU, a testing process will occur and it may be placed in BL. This is similar to how something is made Uber. Tiering is not based directly on power.