[jlouis]

It depends on what perspective you take I guess. From one view, ML is the worse language, but from other views it would be Haskell. Suppose you require a fully formal specification which has been verified in a mechanized way. You have that for Standard ML in Twelf and Haskell has nothing sort of that.

If you look at the concept of being a purely functional language however, it is the opposite with Standard ML being the "worse" animal.

Module system: Then SML got it right and Haskell got it Wrong.

Laziness/Strictness: This is a duality. There are advantages and disadvantages to both approaches so there is no worse/right choice IMO. If you look at the recent stuff on polarity in proof theory it becomes clear that when you latch onto a specific evaluation order, you make some things simple and other things hard.