I'm doing a solo run (only one character in the party; no companions) on Tactician mode. I'm running a warfare-based sword-and-board character. It's been going pretty well. I'm currently in Arx. Bouncing Shield gets pretty ridiculous. With a bunch of points in Necromancy and the Life Leech talent, I generally refill my vitality and magic armor each turn, and since I'm using Strength-based armor, I start each fight with a lot of physical armor. I haven't had to cheese a fight yet, either.
So, I'd say that neither melee-based nor tank characters are useless.
