One thing I've found to work...for keeping loot from going under him or too far to one side or the other is to stand off to the left of him (the Warriors right) a good ways. If someone is standing in front of him, sometimes even when they're 40 yards away the loot will still go under him.
Standing on the sides I RARELY (but sometimes still) have problems with loot under the Warrior.
Did have a CC drop under him about a month back though and I had to leave the area and come back, only to find that it was weaker than my other versions. --- XBL GT: Ki11er Six (ones instead of L's and a space between the two words) Various Borderlands 2 glitches: http://www.youtube.com/watch?v=ZgdactVBsYk