Ok, well, I'm too lazy to look at all of those comments, so if someone's already said something, then WHATEVER.
Metagross.
Moveset is okay, but a few little tweaks should do it. I used a certain set when I went to the VGC, and it worked somewhat wonders.
First off, why the Natural Gift? That's...pretty weird. Well anyway...
Metagross@Steel Gem
-Bullet Punch
-Zen Headbutt
-Earthquake
-Protect
Nature: Adamant
252 HP/252 Atk/4 Def
Believe it or not, Steel Gem Bullet Punch does MASSIVE damage, almost.. well, kinda almost as much as Meteor Mash. Correct me if I'm wrong, but it does the same amount of damage as an Iron Head, but with priority instead. And remember, priority is a huge part of the game. Zen Headbutt to hit the annoying Hitmontop and such, which counter your team pretty well. Earthquake is for other steel types, or any threatening Fire-types, like Chandelure.
Just letting you know, this Metagross is meant to be a kind of physical wall, and Rotom-W works very nicely with it!
ALSO!
You might want to include DW Cradily on your team. It too has Storm Drain, and even benifits from the Sandstorm, since it's a Rock-type. With Grass type STAB moves, it's one of the most perfect rain-team counters. So maybe ditch that Gastrodon of yours (sorry 'bout that, Gastro) and sub in Rotom-W. I DUNNO, just an idea.
Yeah I know the Regionals are over.. good times there. Hope this information helps during the Nats or Worlds! BAI