Some last minute changes I think I am going to go with...
Since the campaign is low-magic, I have been toying with the idea of adding a level of Wiz into the mix for some easy 1st level spells that will help more than anything else. I still love the Grappling Block, and have developed a plan to get it at 6th level.
Again, this is a 4th level build, 32 point-buy, with +1 at 4th level.
Fighter2/Monk1/Wiz1
Str 10, Dex 16, Con 12, Int 14, Wis 17, Cha 8.
HP: 17-36, average ~25 (was ~27). AC: 16 (see below) BAB: +2 (was +3)
Fort: +6, Reflex +5, Will +7. (was +6/+6/+6)
Feats: Weapon Finesse (unarmed strike), Expertise, Combat Reflexes, Improved Disarm, Iron Fist. From monk: Improved unarmed strike, stunning fist.
5th level: pick up a level in Monk, get Deflect Arrows free.
6th level: another level in Monk, get Grappling Block.
Advantages of a level in Wiz:
At Int=14, he gets an extra spell at 1st level, and 3 cantrips. Spells known: Mage Armor. Magic Missle. Summon Critter. + cantrips (prestidigitation, flare, dancing lights, ray of frost)
With mage armor in battle he would have a +4 to his AC, total=20, making him so much tougher to hit. You can't ask for much more throughout the levels, and I can see this monk casting it on himself at 20th level before tumbling into the mix.
I was considering Dodge and Defensive Strike to really pump up the AC, but I will save that for future levels.