The big problem I see is that we have only 1 version of blockConfig.xml (in which order the textures are stored within the texture files) and the whole pack is 50 MB big.
A single text file (blockConfig.xml) downloaded twice? A few KB bandwidth wasted.
A 50 MB texture pack downloaded twice? You may pay at the end of your month (dependent on to who you pay for your internet).
Automatically changing texture packs may lead to admins to change them more often.
I would like it, but I dunno if it would be good for all players.
MineCraft will not have this problem - obviously if you know that each texture is a single file, not 16x16 textures glued together in one big file.