I run a Nurgle DP just like yours - Daemonic Flight, Iron Hide, Mark of Nurgle, Cloud of Flies, & Noxious Touch. It's not cheap but it is very versatile. I only actually run 1 Heavy support in 1000-1750 points games, I like to take 2 Greater Daemons & stock up on troops & elites.
So, maybe think about a Greater Daemon too instead?
& yes, terminatormonkey is spot on - Bloodletters are born anti MEQs; however, I suggest you only take them if you think you can get them into HtH against your opponent, I personally never seem to get them there enough against the SM armies I play (and I play a lot of IG and Tyranid) but that might be my problem. I just think Bloodcrushers are so much better, so I leave troops slots to Plaguebearers and Horrors.