Gruz is interesting, but I think there are better options for the long game strategy. If he boosted off of bleed stacks or curse, I think it would be better. Heck, a chance to auto kill based on bleed stacks could be cool. I like the look and idea, but I think it could use a better execution.
My hopes that they would buff Gruz, a cool-looking troop (well, except for that inflated scythe), before release are dashed. (I was hoping for at least splash damage, or inflicting the curse+bleed on all enemies,.) With that third trait, it seems intended to be a turn-ender, particularly on skull-looping teams.
But a spell that has no board control, real damage, or enemy debuffs doesn’t seem to have any spot in the meta. Aimable curse is interesting, but won’t help you against the powerful stealthy troops out there dominating the game. Gruz sadly seems like a lesser version of Sledgepaw in many respects.