There are two issues I see from my point of view.
One, I think we should be able to halt the version reply and have our own custom version reply sent out. For one thing, people already know about mIRC. If they don't their out of the loop.
Two, trojan makers are going to find out a way to bypass the rename block and changed file block. It's just going to make it a bit harder for the newbies to trojan making I assume.