Upon more reflection...
From the Preface to the Haskell 98 Language and Libraries Report:
Haskell 98 was conceived as a relatively minor tidy-up of Haskell 1.4, making some simplifications, and removing some pitfalls for the unwary. It is intended to be a "stable" language in sense the implementors are committed to supporting Haskell 98 exactly as specified, for the foreseeable future.
In other words, we already have a stable branch of Haskell. Why, then, are we so paranoid about introducing breaking changes in the development branch of haskell? Why are we stuck without the class system extension proposal? Why is Num so still so horribly mangled? Why can I not 'map' over a Set? Why must I use lists of characters if I desire standard sorting? Why can I not get a good error message from read? (If you answer "because H98 is obsolete", then file this away as a must-read after H' is released.) Stefan