Your main doesn't need creeping death and piranhas though. Only the CC doctor which is already crippled in DPS because he doesn't have a MoJ losing out on 100%.
By adding the Piranhas with 15% damage to the CC doctor, your now making your other 3 doctors go from your stated 1.9m + 15%, getting close to 2.2m DPS netting you 300k dps sheet damage for 1 skill. That's assuming the cc doctor is doing 0 damage which he isn't
Throw a Strongarms on the CC doctor, and now you have up to 30% more damage 30% of the time. Which is another 600k dps, or averaged out 200k. In total adding this one ability will net your group 1.5 million dps group buff.

Bottom line you can have the CC doctor do 0 damage and this is a net dps buff.