I had to do a full windows re-install a couple of weeks ago so i can relate to this issue.
Luckily i had most of the big patches already on my system that i downloaded using uTorrent.

There were a few patches however that i hadnt used uTorrent for, for some reason and the official P2P utility is absolutely woeful and was offerring completion times of over 45 hours. I gave up on the official utility and used uTorrent to complete my patch set.

Lesson learned, but this does not help someone that is new to FFXIV and faces rediculous download times for their patches that isnt accustomed to the uTorrent method, and for those new players it creates a terrible 1st impression of the game, so i would agree that having a download repository would be a decent idea.

Having said that, with 2.0's arrival i would like to hope that they will consolidate/obsolete a lot of the patches we currently have to endure if we have to face a re-install.