on one or two accounts, it is not an issue - I have 8 pop accounts and the master domain - thats 9different sorts!
OK, I am not comparing like for like, but with a certain other product, you can sort by account (column) and then drag/drop in to relevant account.
A way around this is to have a 'save sent messages in account folder' or similar.
I dont want to sound aggresive, but you have to get of the 'this is the best thing and way of doing it'. A vast majority of people are coming from one or two major email products, where certain functionality is is used daily. DOnt forget, Redmond had been doing email a few years longer than most other players and they do have some good functions that it might be worth adapting!!!!