I think that should be fixed as well, but it would be tantamount to a new language. 

I guess you need some kind of versioning system for the libraries. Why not put them all in a public source control server and have ghc force people to say which snapshot they wanted. That would be your final breaking change, and it's a one-liner in the Makefile. Then you could thrash around as much as you liked and people like me would have nothing to complain about. Naturally, the compiler itself should keep supporting old modes.

Adrian.