We use to draft same way we draft item cards. deal out cards instead of take 2 and pass its take 1 and pass. Do this three times.
Alternatively since I have every hero including Masmorra we now get to have a roster of 10 heroes in our guilds and can swap in between scenarios so draft up to 10 heroes and pick 3 for each game.
With a large roster, I've been wanting to make campaigns with large rosters and perma-death heroes.