I'm rather looking forward to this upgrade for a few games. Methinks that games like Mass Effect, GTA and possibly other open world games + all games that have lots of texture pop in will be vastly improved using this feature.
That said, I'm sure that the graphics won't get better as in better texture sets. They will get better as in 'loads proper texture in time now instead of too late' though.
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Offtopic:
I can't believe I'm actually reading posts here that say there already are (for existing games) 2nd sets of ultra-high quality textures installed onto the DVD for a feature that didn't exist when the games where developed.
Not only that, but this extra set of textures apperantly also takes no space (well no real space anyway) on the disc because of secret uber-compression that manages to make these vastly bigger datasets so small they a) fit as an extra set and b) still look better than the textures (which are usually stored in a compressed form on the disc anyway) already available.
Now, I could go and explain just why this is extremely unlikely (read: no way it is true), but I don't think a three page long discussion about the merrits of compression and its real-life limits is proper for these boards.