The other core common of the deck, a lot of the damage of the Mountain Vargath will come from Shale Slingers, more often than not protected by the other tough units in the deck.
Because they are ranged, it is very easy for them to be both in Sunderved’s area of support and still able to target enemy units, even when Sunderved is playing extra safe. Having 1 or 2 Shale Slingers out at all times is very common play for this faction.
Slingers also allow the Mountain Vargath to not worry about finding flanks of attack and be able to easily focus fire. A Brute with two Slingers behind can all attack the same spot, making it good versus high life targets and gates.
A common trick with the Slinger, is using a friendly melee unit to destroy a unit that is protecting the enemy summoner, then use the Slinger to target the summoner (no longer protected). This is a big part of how this faction threatens summoners.
In general thanks to Slingers, the Mountain Vargath are extremely good at focus fire which is why it is often very hard to defend from their pushes, as the common strategy of reducing flanks is not as viable versus the Mountain Vargath.