How did I know Darvin would play as an Assassin?
Actually I considered Bloodmage initially, but I went for the "low-lying fruit" with the Assassin first. Goblin Bloodmage is going to be my second attempt; I'll be aiming to add faithless to my score for a total of 25 points.
You provided a good example of why I think that you overvalued Unstoppable. You basically got it for free with Ding! Max!
Every class will have advantages with specific badges. I'd say Assassin's edge with purist was far more influential to my decision to go with him than his edge with unstoppable.
Edit: I'll probably try the same thing (if I get a chance), except see if I can replace Purist with Warmonger for an extra point.
I was thinking the same thing; go for it.
Also, don't be afraid to post lower scores. Your highest score is the one that will be used, but additional runs can give us an idea of which badges are over/under-valued.