That Troll Fighter(4), by the way, has other worries than you seem to account for. Fire and Acid don't produce subdual damage, they produce real damage.
There's also the fact that the troll will have lower save bonusses ( base 9/3/3) than the human (base 9/5/5); not all that many extra hitpoints (assuming each starts with a 10 CON before race, the troll will have 6d8+4d10+60, the human will have 15d10 - averaging 112.5 for the troll, and 87 for the human); a much lower BAB (+8 for the troll, +15 for the human); far fewer feats (7 for the troll, 15 for the human); fewer skills at a lower maximum rank than the human (skill points will be 1 per level/HD for the dumb troll, 3 per level/HD for the human - assuming each starts with a 10INT before racial modifiers; max ranks will be 13 for the troll, and 18 for the human).
The troll has advantages, yes. But ... walk into town. Teh human can walk in,no problem, at most he may be asked to leave his weapons at the gate.
The troll, if he gets within a half mile of those gates, will prompt the assembly of at least one hunting party, who will scoure the countryside with plenty of acid and vials of alchemist's fire (and spellcasters galore, if available), with no other purpose than to reduce the troll to a smoldering pile of stinking ash.
Now that, sir, is a disadvantage.