I understand the need to keep a consistent record of purchases, so, of course, that shouldn't be messed with. I wonder if there is, instead, a way for us to 'hide from list' any purchases that we no longer need access to? That would help.
I'm sure the original thinking is that once you download an app, you don't need to download it again and the list is just for 'emergency' purposes. I doubt they expected us to all use it so much. Personally, I am responsible for the iPad accounts and support at my work, so I'm constantly installing an app, deleting it, reinstalling it later, deleting it...and so on. Yet there are a LOT of apps I know I'll never need to install again. It would be great to be able to hide those ones from my list so I can access the others more quickly.
A suggestion for Apple...I would love to hide some apps completely, but if I could at least hide them from my list in iTunes (you know, the App page when I'm organizing my iPad), that would be a tremendous help. When I'm on the app store and go to the purchase list, it isn't as big a deal, although it would be nice there, as well.
Having the ability to hide an app we don't use might actuallly be a way for Apple to track apps that are downloaded by not actually used or kept. More fun stats!