It sounds like a waste of time. If you are prohibited from improving your roster by trade, then that takes a major element of the competition/strategy out of the game.
I played in a league once where there were virtually no trades, not because of rules but just because most of the owners were brain-dead/unimaginative, and that sucked too. There's only so many ways you can improve your team picking up guys from waivers.
You've got a diamond, You've got nine men
You've got a hat and a bat, And that's not all..