Parsec as a Dependency?

Hi Caballers, now that .cabal files are getting a more complex syntax (due to configurations), I'd really like to use Parsec instead of lots of hand-written and hard to maintain parsing code. By getting rid of ReadP-based field parsing, we'd also get proper error messages for field values. At the Parsec homepage I says that it's now included by default in GHC, Hugs and NHC, so it'll most likely be present on any sufficiently recent system. What would be arguments against this proposal? / Thomas