tidy and tidy-devel in devel don't provide libtidy or libtidy-devel, which will break existing packages using them. At the very least, the -devel Provides should be added. And fully versioned, as usual. (There's also one commented %{epoch} in the specfile to get rid of, while at it.)
What existing packages refer to libtidy/libtidy-devel?
For example my local mod_tidy package. But that's not the point, there's no way we can know what refers to it outside Extras. The point is that incompatible packaging changes shouldn't be made without _very_ strong reasons, and there are no such ones in this package. If you insist on getting rid of libtidy*, do it after a transition period, IMO in FC-6 it would be ok'ish to drop the Provides.
Fair enough.