So I propose that we add an additional stricter WriterT (under say, "Control.Monad.Trans.Writer.Stricter") which is internally implemented as StateT, but hide the constructor so we don't expose the implementation:

Nice work. If we end up adding a new module (instead of e.g. replacing the current one), lets try to have a more descriptive name. The -er names quickly get out of hand: New, Newer, MoreNewer, Newerest! Better to include a word that explains in what sense the writer is strict.

Let the bikeshedding begin!