Unless they make massive changes to the engine between then and now - you really have nothing to worry about.

For the most part a shader will not care how the model is put together or what you level looks like. The only thing that you will have to consider is that adding things like bump maps will effectively double your texture memory requirements (not quite - but safe assumption to avoid hassles).

For the level geometry - it will depend entirely on how/if/when they implement geometry which can recieve shaders. Depending on how that is done, you will likely have to completely recompile the levels for the new specs - and might have to rework a number of areas.