Raven would also be shorter if multiplayer was not a thing.
Putting the length of the card to one side, my view of Raven is that he is servitor of control (in the conceptual sense). If you want lots of bullets and to shoot a man just to watch him die play Stone, Raven is more subtle. He clearly has synergy with protection racket and the 108 bandits, he may also play into a more aggressive spirit fortress build which forts up on an opponents deed.
If they can afford the starting ghost rock I think Grimme may also find a home amongst Hex control decks. If you can boot out your opponents dudes using Leon paralysis mark, phantasm and/or mark of pestilence. Raven lets you claim an extra control point at your leisure. A blood cursed dude is also unlikely to pick a fight with a dude at a deed marked by Raven allowing you exert even more pressure. It will be interesting to see how he develops the meta as the -2GR is a hard hill to climb if you want to start skilled dudes.