Examples:
Stunning melee attacks (including shield bashes, head clonks etc.)
Shield-rushes/Bull-rushes (better than the normal kind, i.e. more powerful/reliable.)
Exceptional tripping ability, trapping people on the ground.
Throwing rocks or weapons to interrupt spellcasting
Ranged AoOs due to exceptional combat awareness (even when not using a ranged weapon - again, throws rocks, daggers, etc.)
Throws/flips/moves enemies.
Chucks dirt/dust/powder in enemies eyes/faces.
Tricks enemies into overreaching (in a non-mind-control way).
Disarms, sunders, etc. better than normal melees.
Basically, you could just focus on all the utility/movement-control options available to melees, and upgrade them. Call him the Thug, or Mercenary, or Veteran, or whatever, cooler name you can come up with.