Necessary but insufficient

It would help. It would more than help; I have a hard time imagining them being functional without it. The necklace of natural attacks or scorpion kama are generally necessary for Monks. That said, the necklace of natural attacks does exist (as do similar items in Pathfinder), and it’s not nearly enough to make the Monks good.

The Monk’s problems are problems of design: the people who wrote it evidently had no clear idea of what a Monk was or should do. Thus it receives a mish-mash of random abilities that do not synergize (and frequently contradict one another, see Flurry of Blows and Fast Movement).

To “fix” the Monk, one must first come up with a clear vision of what the Monk is supposed to be and do, and then most likely rebuild it from the ground up focused on that vision.

Or simply use one of the many classes that can effectively model one or more possible visions of what a “monk” should do, without any levels in the “Monk” class. The Cleric and Psychic Warrior are both Open Game Content and quite capable of fulfilling most roles you could imagine for the Monk, for instance. I’d argue that it’s entirely reasonable to treat a Barbarian’s Rage as “Zen Focus” and waive the non-lawful requirement (which I’d further argue is dumb to begin with). Such a “Barbarian” multiclassed with Fighter for combat maneuver mastery and perhaps taking Improved Unarmed Strike would make a decent monk. And if you have Tome of Battle, the Swordsage also does an excellent job.

These options definitely help make the monk have some unique and appropriate abilities

It makes the monk mobile again, which it should have been in the first place, and makes some of the monk’s features work a little better.

It still means the monk gains very little as he levels up; Flurry of Blows is better, Fast Movement is marginally better, but those are features gained at levels 1 and 3, respectively. Why is the monk getting more monk levels? Most of his class features are strictly limited, too limited to really do much with.

Worse, MAD is still a massive issue: the monk is going to have low-ish AC, low-ish attack rolls, low-ish damage, and quite-low HP. His skills will quite likely leave a lot to be desired, particularly with an apostle of peace in the party who is making combat a decidedly secondary option.

Which brings me to my primary objection...

This still leaves monks with no options aside from beating on things

You’ve made the monk a considerably better combatant. Not a great one, but now monk 2 becomes a fantastic dip for a lot of characters. Maybe you delay the standard-action Flurry and Dance of Death features to force people to stick with monk to get those, to eliminate that, or you don’t care about those because the character already has double-digit monk levels and you don’t plan on re-using these houserules.

But what happens when combat isn’t the answer? I mean, you have an apostle of peace in the party (which, as an aside, I consider a big mistake to allow); combat is not going to be the answer fairly often. Monks only get 4+Int skill points per level, have way too many competing requirements to have significant Intelligence, and have almost zero class features that dramatically affect non-combat situations. Some mobility, sure, but that’s about it. They are feat-starved, so getting non-combat feats is going to hurt, though it is possible.

This is a serious problem. In fact, it’s the entirety of the reason the barbarian is a Tier 4 class: yeah, the barbarian can insta-kill anything it can charge, if you build it that way. The damage numbers available to a barbarian charger are patently absurd. But it doesn’t matter because any problem that cannot be solved by charging it, cannot be solved by a barbarian charger. He just has no meaningful options for doing anything about it.

The monk problem is not purely a numbers problem

The monk has number problems, that’s absolutely true. Number of HP, the numbers that serve as attack bonuses and damage rolls, the number of actions he gets per turn being insufficient to use all his class features.

But they aren’t the only problem, or even the biggest problem. The biggest problem is that the authors didn’t really know what a monk was supposed to be when they designed it. They gave it a smorgasbord of class features with little coherency. It’s a class that’s billed as a non-primary combatant, a learned man or woman with background in philosophy, religion, meditation, diplomacy, and so on, none of which the class actually offers aside from tossing some relevant skills on the monk class skill list.

Solving this problem, solving it for real, really means starting from scratch and determining what you actually want from the monk class. And it’s probably not going to be very similar to the one in the Player’s Handbook.

Best / generic solution: just replace the monk class

The monk class is poorly designed. They made mistakes, they’ve even owned up to some of those mistakes, which is depressingly rare for Wizards of the Coast. It simply doesn’t provide features that enable it to perform in the ways its own fluff claims it does.

The best solution is just to use a different, better class. There are some great options for this, and two are on the SRD.

The first is the cleric. The cleric can, with Complete Champion, take Travel Devotion to move as a swift action: moving as a swift action and full-attacking as a full-round action is a lot like moving as a move action and full-attacking as a standard action. A cleric can take Improved Unarmed Strike, and then Superior Unarmed Strike from Tome of Battle if that’s available, or he can finagle his way into the Sacred Fist prestige class (a monk dip may be worthwhile there for the earlier Stunning Fist feat). And clerics get spells, very powerful spells that enable an enormous amount of versatility.

The second is psionics. Psionic characters can also take Improved/Superior Unarmed Strike, but if Secrets of Sarlona is available, they have a far-superior option in Tashalatora, which allows levels in any one psionic class to count as monk levels for unarmed strikes, flurry of blows, fast movement, and the AC bonus. Psychic warrior (from Expanded Psionics Handbook or the SRD) and ardent (from Complete Psionics) are both ¾ BAB classes with Wisdom as a manifesting ability, which is an awesome fit for monks. Psychic powers are extremely similar to the ki powers of the monk (and, in fact, many other RPGs make them the same thing, for instance D&D 4e).

The third is the swordsage, from Tome of Battle. Arguably what the monk should have been in the first place, this class is almost identical to the monk in flavor, but gains far more potent class features. Their AC bonus applies in light armor, rather than strictly unarmored, their maneuvers offer far greater versatility and flexibility than merely flurry of blows and Stunning Fist, and they have 6+Int skill points and much less MAD, making them far more likely to be able to put their skill list to good use.

So I really, strongly recommend using one of these classes. The apostle of peace is an extremely powerful class, one of the most powerful in the game (for several levels, it is actually ahead of the cleric, druid, and wizard!), and without doing something drastic you will have an almost literal case of Angel Summoner and BMX Bandit.

Alternate / tailored solution: play up the Enlightened Fist aspect of things

As your monk is actually an enlightened fist, that opens up other interesting alternatives.

First, eliminate the non-spellcasting levels of enlightened fist. The character already has two monk levels, so that’s quite penalty enough.

Second, kill the MAD, kill it with fire. There are feats that allow a monk to use Cha for monk class features; an enlightened fist shouldn’t need those, it should just use Cha. So Cha-to-AC, Cha for saving throws to Stunning Fist and Quivering Palm and whatever.

Swapping sorcerer spellcasting to Wis instead of Cha is also an option, if you like, though fairly unusual.

Third, he’s going to lack skill points in a huge way. I am strongly of the opinion that only Int-based full-casters deserve 2+Int skill points; neither the monk nor the sorcerer qualifies. Monk should be a 6+Int class, minimum, and sorcerer 4+Int. Up the skills per level of enlightened fist to 4+Int or 6+Int, and make sure it has all monk skills as class skills, at the very least.

Fourth, some kind of “cast a spell when you hit someone” class feature would be awesome. Some other classes have features like this to consider:

• Arcane Flurry: the enlightened fist can cast a touch-attack spell into each weapon strike of a flurry, à la the duskblade’s Arcane Channeling (Player’s Handbook II).

• Spellwarp: the enlightened fist can change any targeted or area spell into a touch spell to channel into a flurry; if it had offered a Reflex save that’s gone, replaced by the attack roll, à la the spellwarp sniper’s Spellwarp (Complete Scoundrel).

• Quickening Strike: by expending a use of Stunning Fist during an attack or full-attack, and successfully landing at least one hit, the enlightened fist may cast one spell he has prepared as if it were prepared with Quicken Spell, but without any adjustment to its spell level and ignoring the sorcerer’s inability to use Quicken Spell, à la the jade phoenix mage’s Quickening Strike (Tome of Battle).

Between the three of these, the enlightened fist can fuse his spellcasting and his martial skills well. With the improved spellcasting, reduced MAD, and better skills, he’ll also have plenty of options for non-combat situations.