This is practically giving the Monk a full Base Attack Bonus anyway, so I say, go ahead and give it to them.
If that third iterative attack and the increased rate of achieving a minimum Base Attack Bonus for the purpose of prerequisites is too much of a sticking point, then how about “+1 competence bonus to attack rolls (standard attacks and combat maneuvers) with special monk weapons and unarmed strikes at 1st level, increasing by 1 every four levels thereafter (+2 at 5th, +3 at 9th, +4 at 13th, +5 at 17th)”. Taking that and the medium Base Attack Bonus, you get accuracy equivalent to any full BAB class, your extra attacks are more derivative of your Flurry of Blows than your iterative attacks, you don’t add your BAB to Sense Motive, and you still qualify for feats and such with BAB prerequisites only as early as a medium BAB allows anyway. You could even make this number dependent on your Wisdom bonus, so that the competence bonus cannot exceed it.
Alternatively, Calronmoonflower of the Wizards forums came up with a smart idea. He called it the Flowing Fist and basically, you lower your unarmed attack damage to a smaller damage die (provided you have a smaller damage die) and increase your unarmed attack rolls by the same amount.
Kind of like this:
Medium Monk
Base damage 1d6 1d8 1d10 2d6 2d8 2d10
Lowered to 1d6 - +1 +2 +3 +4 +5
1d8 - - +1 +2 +3 +4
1d10 - - - +1 +2 +3
2d6 - - - - +1 +2
2d8 - - - - - +1
Leave the Maneuver Training where it is, let it cover the combat maneuvers, and the Flowing Fist fixes the unarmed attack accuracy. This wouldn’t fix the special monk weapons, of course, but I don’t really know how to address that.