I think tiling is coming for r600g (arlied is working on it), Z is not yet implemented in any ways.
Pageflipping might be in the kernel already.
I have no idea about fast clears.
Are there plans to do these in the foreseeable future?
By the way, this new compiler won't happen in the near future, so by the time it is done radeon might very well be at the point where this will be the biggest bottleneck...
I also think that there will be an intermediate solution here. Just like old ati and nvidia chips are not suitable for gallium drivers I think some cards will have this unified compilers while older ones will have to live with what they already have.
Just my not-very-insightful opinion...