I've made a few of the recommended changes to the team, and updated the OP correspondingly. New stuff is in bold. I laddered a little bit tonight, I'll probably test them out more tomorrow.
EDIT: A couple notes from my scattered thoughts:
- I can divide the team into three components; the trifecta of Mienshao, Scizor, and Rotom-W that act as scouts and attackers; the two supporters, currently Tyranitar and Skarmory, who put up entry hazards and serve as pivots; and a late game sweeper, currently Excadrill, to close out games.
-Looking at those two supporters, it is not imperative that I have sandstorm (because I can just change the late sweeper to something that doesn't need it); I just need the two functions named above. So perhaps I change to Jellicent and something else (Deoxys-S?), and change the sweeper to Conkeldurr or something.