Torodin and Quen somewhat overlap with similar uses, both are good against commons, especially those in tight formations and can help put pressure on players that are playing defensively. And that is fine, since this is a situation that is common for the Mountain Vargath to face.
Torodin is probably the better of both options, and less reliant on working as a team, as any other unit in the faction. Often Torodin can run to do his own thing, but only if you can really afford it. While other decks may struggle to get to such a high cost unit, the Mountain Vargath high life units often survive enough to give time to save up magic without giving up on pressure and board presence.
Torodin is also very good at threatening low life summoners with his climb ability, and some of the abilities of Mountain Vargath like Form Up and Ramming Advance.
Torodin, as most other high cost champions is good to give you an early window to burn your deck for magic, knowing that as long as he is still coming in the deck, you will have a way to spend that magic, and as all other champions of this type, he’s great to have against factions that summon a lot of commons and give you a lot of magic. Having a way to spend that magic is good, especially when it is to summon a champion that is particularly good against commons, as Torodin is.