Simon Peyton Jones suggested the following changes:
1. Move specification of enumFrom and friends from 3.10 to 6.3.4
2. Specify that for bounded types, (succ maxBound) and (pred minBound) are errors.
3. Specify that succ and pred on numeric types just add/subtract 1 (subject to (2) above.
4. Rewrite D.2 to talk about deriving only, not about Enum in general.
5. In Appendix A, the Enum class defn, add comments to explain that the default methods only work for types whose fromEnum/toEnum range fits=20 inside Int. In addition, I suggest that, since it is widely agreed that the instances of Enum for Float and Double are highly unsatisfactory, the report should give these instances the same status as n+k patterns have (in 1.4 of the recent revision). In particular, their use should be "discouraged", and there should be a warning that the instances may be "altered or removed in Haskell 2".
It might clear the ground somewhat for Haskell 2 if there were a new section containing a list of deprecated features; we can probably think of some other things which should go in there. In addition to what's said for n+k patterns, I suggest the standard explicitly encourage (but not oblige) conforming compilers to issue warnings when deprecated features are used.