If you don't necessarily want to play a pure warrior, some other skills that don't rely on high intelligence (like summons, buffs) or dexterity (that can be boosted later with equipment bonuses) can help quite a bit.
A point in Aerothurge would give access to Teleportation and Thunder Jump (the stun effect wouldn't trigger as much with a low intelligence, but it gives a relatively low AP way to get into the thick of battle). A point in Geomancer would give Midnight Oil (slow opponents, or set up for fire surfaces and smoke clouds), Boulder Bash (no line of sight required) and the spider summon. The scoundrel skills Walk in Shadows (invisibility), Winged Feet (lets the character walk over surfaces unaffected) are useful in and out of combat, and Fast Track and Trip could be useful (more so after getting some dexterity bonuses); the adept skill Cloak and Dagger (teleport) can also be handy.
Another character could also pick up a level or two of Witchcraft, particularly for Oath of Desecration to buff the warrior.
