I'm leveling up warriors at the moment. In the 3 DK team, I am wondering how effective it would be to go to 2 DK's and drive as the warrior.

DK's are IMO easier to manage as drones since so much of their DPS and effectiveness is ranged. The warrior on the other hand has wreckstorm for huge burst + mortal strike to reduce healing effectiveness even further.

Or maybe even go to a 3 DK 1 War + healer team.

While the MS debuff is only 10% right now, Bliz has admitted that 10% is too low right now with 200% crits for healing and they have dropped a hint that 20% MS(all MS style debuffs) would bring it in check.