Adding my support for this too; I don't use a lot of Haskell packages myself, but binNMUs for these packages would make a material difference to overall Debian amd64 reproducibility[1] -- getting the suite to almost-or-more-than-90% rebuildable by anyone independently.
(...and thereby making the expectation and believability of bit-for-bit rebuildability from freely-available source for the operating system more realistic and commonplace, something that should help everyone. I'm being verbose to explain why I'm supportive despite not using many of the subset of packages here myself) [1] - https://amd64.reproduce.debian.net/
