It actually looks like a second Diablo themed map is in the works before any Starcraft stuff. I'm guessing it takes a long while to get all the art assets done for an entire new tileset.
Pretty sure his go-to ult will be the PBAOE damage one. I don't see how lamb to the slaughter would actually help you win a team fight. It is basically a (much) worse VP for that purpose.
I could see lamb to the slaughter to be used with a heavy AoE comp to make sure it lands on most or all of an enemy team.
It isn't until 20 that it chains everyone. At level 10 it just chains the closest enemy.
On the trailer thing they show it cast on a group of people and it only catches one, so it's fairly bad in that regard. It's really only to lock down an annoying evasive hero like Valla or Lili or whatever, so you can beat them into the ground, but in teamfights it's not gonna be that helpful a lot of the time. Then again I don't know how good the hero will be at all in teamfights, looks like you charge into the enemy and either kill him then die, or just die.
If Butcher initiates a team fight I'd see him having a hard time. It seems like his ideal role would be to charge the backline after an initiate and try and kill as many as possible back there. I could see him with maximum Meat and if he takes the Blood Frenzy talent at 16 (+1% att speed per Meat) he could put out absurd damage.
