A unit need not have 5 defensive stalwarts on the floor to be a good defensive unit, and I think in the case of Ivey there could be some addition by subtraction if you reshuffle the lineup in other ways.
One way, and the way that would make
DAF86 happy because it would allow him to gloat over this entire board, would be to move Sochan to the 4 and Wemby to the 5 and add an additional wing who is a good defender, say for example OG.
Ivey
Vassell
OG
Sochan
Wemby
Is likely a huge upgrade on the defensive end over what we play now.
I do agree thoguh that a trade like this is likely a very long shot.