One simple solution is to go for quantity instead of quality. A Cimmerian Berserker gains 35.57 hitpoints per point of vitality, and 0.4 % damage bonus per point of Strength. The increases across 20 levels are meaningful but not world-changing, considering that they start with a solid pool of hitpoints, and they have a good base melee modifier.
Some Black Hand T4’s have great stat improvements. They start with lower scores than a Berserker, of course, but they also level up a lot faster and can reach well over 3000 hitpoints. They can handle themselves pretty well against NPCs.
Now, against PvPers, thrall stats alone won’t help defend your base because the thralls are idiots, and unless the attackers are also idiots, they can dismantle whatever thrall defenses you have if you’re not there to fight.