Alright, here are some things to add/change/fix:
Overview
A trivial change, but Salamence is certainly not a top-tier threat. Garchomp, however, is a great example, so keep it.
Actually, Abomasnow gets 2HKO'd by Starmie's LO Psyshock factoring in Analytic. Specify what these resistances are.
Abomasnow will RARELY be on the battlefield for more than 5 turns, so this point is moot, especially that SubSeed is no longer a set.
This point is a little misleading. Abomasnow certainly does not wall lots of the metagame—in fact, it's really nowhere near doing so. It's not really "good" either—yes, it's good at doing what it does, but this is pretty limited to wallbreaking.
Moves
Move this to OO. Ferrothorn takes enough from Blizzard, and Mega Aggron and Forretress are much too trivial to run Focus Blast for.
Move this to OO as well. Substitute really sucks on a Pokemon with a Stealth Rock weakness, a tendency to be forced out by a ton of things, and a lack of reliable recovery (Giga Drain doesn't count, due to the low amount of Pokemon it hits).
Set Details
Giga Drain is slashed first, so this should be the main spread in the set, with the current one moved down into Set Details.
These should also be in OO.
Usage Tips
You're missing this section entirely.
Team Options
Be more specific—what are some sweepers that appreciate the lack of the specific walls that Abomasnow takes care of?
Remove Tentacruel, it's a bad Pokemon in OU.
Make sure you specify why.
Like?
Other Options
Growth is simply unfeasible on such a slow and vulnerable Pokemon, it should be removed altogether.
Checks and Counters
Fix up this section to match the site standards, which you can read about
here.
Fix all of those things and add a Usage Tips section and I'll stamp this for you.