Mixed feelings. On one hand, it really hurts what the "what if" aspect is supposed to be. "What if we couldn't use a lot of guys we want to use because using Dennis Rodman clones is the way to win?"
On the other hand, "What there were two Michael Jordans?!"
I play in leagues that allow them and some that don't. Draft leagues & prog leagues don't, and they're my favorite, but OLs do... and unless I'm just trolling or have a specific purpose to not use them, I won't give up the competitive advantage they bring.
I also don't tell people how to spend their money, so if they want to use clones or not use clones on their squad, that's 100% cool with me either way.