This is very true, no thing in life comes without trade-off's.
Forcing picwins on to the desktop if they want a custom size is a trade-off i personally could live with. Then again i never felt a need for different size #channels/?queries either thats not too say others havent though. So im a bit biased towards an SDI interface and thus only see the benefits of switching.
I honestly dont see the need for cascading windows when you can already switch easily with ctrl+N, toolbar, treebar. Tiling on the other hand i do get for which grids could work in an SDI.
I know you specifically do a lot of custom window work,
I'm flattered and i have in the past but i think you may mistake me with Foshizzle (also has an emoticon as avatar) who is currently more active with picwins especially on this board.