The fight with Braccus is one such fight. Yea you can hide behind walls, retreat, etc... Do what you gotta do. Or you can smash it down like a man(or in this case two men and two women).
Use your mind, this fight is ridiculously easy when you think about it. In fact, you probably already got taught how to win the fight just outside the church. When you killed Twins Joined by Fire in the burning ruins what happened? He dies and lava pours from his corpse, probably killing your melee. At least that's what happened to me. Time to use that against old Braccus and his minions. When you start the fight, use a knockdown on Braccus. If it doesn't stick, it's no problem, you'll just take a bit of a beating. All other efforts need to be focused on Twins. He'll die pretty quick under concentrated assault. When he does, he also oozes lava from his corpse. Now comes the fun. Use teleport, or a teleport scroll and teleport the duke and the ghoul who guards the lighthouse into the lava and blamo instant death. Now you can kill Braccus at your leisure. Once it's four vs one he's a push over. Took three turns to kill him at level 8.