If Middle Earth goes anywhere, it should be as the anchor of a 3rd gate... Middle Earth would just look awkward next to the urban locales of USF. IOA doesn't have the space to do LOTR justice. Plus, it would give the 3rd gate a huge IP and something to market itself on.
But MIB is at the bottom of USF concerns (from worst to best attraction):
1. Fear Factor Live
2. Twister
3. Shrek 4D
4. the whole KidZone area aside from E.T. and Curious George (sad to see the monkey is leaving this fall)
5. Animal Actors
6. T2 3D
7. Disaster (everything after is fine or just needs a refurb/update)
8. Blues Brothers
9. Rip Ride Rockit
10. E.T.
11. Springfield area
12. Mummy
13. MIB
14. Transformers
15. HE
16. Gringotts
Horror Makeup Show and Lucy are fine as well... but MIB is easily a top 5 attraction at USF. 14 years and it's still the best ride of its type by a mile. It has AAs and full-scale sets which is a rarity in Universal rides today, and gives it a unique hook. Not only that but a sci-fi land could easily be implemented using Fear Factor and the mystery plot. Middle Earth wouldn't mesh well with the rest of the park (especially Springfield and KidZone if it connects to those areas of the park
) but I'd definitely like to see LOTR introduced either in the 3rd gate or as a Toon Lagoon replacement.