After a bit of hunting around I found this copy of the announcement video, this is the highest quality one I`ve seen yet, it includes both the editor footage and the gameplay footage as well as the full uncut disscussion with Florent about the game. All in French I`m afraid but theres not a lot I can do about that unless someone wishes to translate it. The full vid is 28mins long and 118Mb for those who wish to know.
TM2 Announcement video uncut 
And here`s a couple of clips of a backstage disscussion/interview with Florent filmed after the announcement.
Backstage interview with Hylis @ FJV Paris `09 - Part 1 15min 77.04Mb
Backstage interview with Hylis @ FJV Paris `09 - Part 2 2min 12.82Mb
Features and details as I have been able to work out go as follows,
Yes there are three new environments but Valley is the only one definately named so far, the others are of an American and Asian feel but these are not their names, One of them is probably going to be called Arena but this is still unconfirmed.
Each of the new environments is a blend of previous styles with much refinement. There has been a major physics overhaul so expect fast but heavier cars with more of weighty stadium feel rather than the almost weightless feel of the Island car.
Custom blocks are to be allowed but it is unlikely that there will be an internal editor for creating them, instead like cars they will probably have to be built in something like 3DMax and imported. This could change though as more details become clearer.
All new lighting system including placeable controllable lights, This will probably seem a bit like the UnrealEd and Radiant systems but as with everything so far details are still sketchy.
The new split-screen mode is to replace the old hot-seat method of 1PC Multiplayer play by the look of things, about time more PC games need this. (it`s quite fun if you know how to do this to UT3 too hehe.)
ManiaScript promises to be an interesting feature, from what can be worked out so far this is probably connected to the new MediaTracker system and will allow you to add dedicated TM-scripting to your maps which can define both define and control various actors,objects and assets within the game As well as give the map maker direct control over other features. One example is the fact that "Moods" are now a thing of the past, instead the environments "Sun" is directly controllable lighting actor and can be moved around the sky or even placed under ground level and switched off. The net result of this is that the sun can "Set" half way through the race so you start the race in Daytime and finish it at night as in the videos. There has so far been no information as to which other actors may yet be affected by ManiaScript but don`t be surprised if you can control IK on blocks so a drawbridge that raises and lowers at different times may be possible.
as I work out more it will get posted.