I don't think changing Best for Long would be "retarded" at all. I'm not saying Long is a much better player than Best now, but he certainly has the potential to be.
Long is also a better compliment to Ba/Shola/Ranger in that he's highly mobile, pacey and runs the channels hard. Also a good target for through balls from Barton/Cabaye.
I like Best for what he did when given his chance last season, and it would be a tough decision to move him on, but Long certainly has the potential to be a very good signing for us.
Also, if we are going to play one up front in some games you could argue that Best is only third choice behind Shola and BaBa.