I usually see Garens build psudo-AD caster with an early Yomuu's and straight up eat people. Now, I dunno HOW they actually do it, but he chews through squishies every one of the few times I've seen him.

theres a reason they dont buff him, he's manaless buffing people like that is stupid because they just spam skills constantly if he is buff he will be way to overpowerd, and garen isnt good on dominion because he has a very strong early gamde but his damage drops of so much late game, which is why he sucks in dominion. if you want to play garen play him in sr where he is balanced.

remember they dont balance for dominion.