I think everyone, even though the hints might not look like they're suggesting it right now, could be a How to Train Your Dragon ride. Madagascar could make sense though as a 3rd movie is in the works.
As for the overhaul to another attractions...I think many are forgetting that (as sad for me as it is to say it) T2:3D was announced as an attraction on the possible cutting board for USF. I don't know how realistic it would be to assumer that but we'll see. Also, E.T. could use some new animatronics as could Jurassic Park. It should be interesting. As for Disaster being rethemed, don't count on it...every time I go it is one of the more popular attractions at the Studios.
I totally forgot about T2:3D! Wasn't Universal Creative talking with James Cameron about making an Avatar show experince? With Avatar being such a big name and with a 2nd film in the works, this could be a great time for an Avatar show to take over T2:3D. However, I don't think this is what the announcement is for. It has been clearly stated by Universal that this announcement will have two parts. 1) Announce what will replace Jimmy. 2) Announce what ride is getting a tech overhaul. So, we are going to be getting a NEW ride in an old building along with an upgrade to an old ride.
I think it is going to be DM since a new movie is coming out and universal owns the IP for the ride to replace Jimmy. It has been the one rumored named for a long time, so it just makes sense.
However, I am still confused on the upgrade part of the announcement. There are so many rides that I would like to see get an upgrade.
1) Spiderman! New projections would make this ride even better. Plus, it would allow them some time to add or fix some new special effects. However, as mentioned before, they would have to deal with Disney to do anything major to this ride, and with the success of HP, I don't think Disney is in the mood to help Universal out any more.
2) MIB! I would love to get new cars for this ride that function better and look nicer. The cars are looking really run down. I would also like to see more special effects added to the ride.
3) Hulk! Another long rumored upgrade for Hulk is new cars that have lights and sound. With Universal currently (or just finished) repainting Hulk, now would be a great time to add in some new cars that would not require much down time. As long as nothing changes to the track itself, they should be able to run the old cars during the day and test the new cars at night. This would allow them to upgrade the ride with little to no downtime.
4) ET needs some TLC, but I don't think Universal will touch it. I have a big feeling that ET is on his way out soon. I think Universal is waiting to see the reaction for the Madagascar ride at USS. If succesful, they have a nice big building just waiting for a new family friendly ride. Plus, they should have all the issues worked out with the ride that has prevented it from opening for so long.
5) Jurrasic Park needs some love. Lots of the effects were not working the last time we rode. I would also like to see them replace the "box" with the car from USH. The car is a MUCH better effect than the "box" that normally never works.
I can't wait for the 19th to get here so they can announce this stuff already!