There is a problem with this idea; it was tried once before!
2nd edition turned a bunch of classes into kits during the early years of of the Complete Handbooks. The idea was akin to this; why make a dozen new classes when you could just flavor the current ones via kits. Thus, classes like cavalier, barbarian, thief-acrobat, assassin, and monk all became kits. Some of them didn't translate too well...
[sblock=Barbarian 2e]Special Benefits: Barbarians are impressive because of sheer strength, intensity, and animal magnetism; this gives them a +3 reaction adjustment bonus in certain situations.
Whenever the barbarian character achieves a reaction roll of 8 or less (including Charisma and racial bonuses), you subtract the modifier. That is, if the reaction is positive at all, it will be even more positive than it otherwise would have been.
That was only one of several takes on the barbarian in Complete Fighter. You left out the following
Beast Rider: "The Beast-Rider is a warrior in a clan or tribe (usually, a barbarian tribe) which has a strong affinity for one type of animal.
Berserker: This is the rager. Note in the Role Section that it states in "In
his tribe, the berserker has a special role"
Savage: Described as even more primitive than the Barbarian and Berserker
Wilderness Warrior: This can be the barbarian with favored terrain.
That's the essence of a barbarian right; a bonus to reaction rolls. No d12 hp, no rage, no bonuses to speed or hatred of magic.
Well, I don't see the d12 or any othe that stuff as the essence of a barbarian.
Rage? The official 1e Barbarian did not rage. I might be wrong, but I don't recall the Barbarian in the 2e version raging either. Furthermore, there is no reason that rage should be limited to "barbarian characters with wilderness skills".
Hatred of Magic? Sounds more appropriate for a specific cultures within campaign setting or a character with a taboo but not something that applies to every barbarian. Among the various small scale societies in our history, magic is osomething that tends to be all around the people and part of their every day lives . Often there is good magic and bad magic. Good magic might help the hunt or a specific activity. It might determine the source of an illness (including the sorcerer that cast it) or heal. It may wash away the contamination from outsiders or harmful spirits. It might detect those that wield harmful magic.
[sblock=Assassin 2e]Special Benefits: Because of their training and experience with the use of poisons, Assassins also can identify poisons used by others. The base chance of doing so is the Assassin's level multiplied by 5%.
Assassins with intelligence of 13-15 get a +5% bonus on the attempt; 16-17, a +10% bonus; and 18, +15%. Further adjustments depend on how the Assassin attempts the identification: sight, smell, taste, or symptoms.
Sight means examination of the poison or poisoned article. Many poisons have a distinctive appearance, or they may have a corrosive or discoloring effect on metals, foods, etc. Identification by sight has a -20% modifier. Its advantage is that the Assassin needn't worry about poisoning himself in the process.
A poison may also be identified by its odor. This carries a -15% penalty. Furthermore, if it is an ingested or contact poison, there is a 10% chance that the Assassin will be affected by the poison, though at half strength (i.e., no effect if the saving throw is successful, and if it's not, normal save damage is applied—see the Dungeon Master's Guide, p. 73).
Taste is a fairly reliable, if dangerous, method of identifying a poison. It carries a -5% penalty. After dabbing a tiny bit on his tongue, the Assassin spits it out. There is still a chance that the poison will affect the Assassin: 25% for injected poison, 75% for ingested, and 100% for contact. The poison's effects, if any, are half strength (see above).
The most certain way of identifying a poison is by its symptom (no penalty on the attempt). The drawback of this method is of course that you need a poisoned character to examine.
An Assassin with herbalism proficiency gets a +5% identification bonus because of his knowledge of toxins extracted from plants. An Assassin with healing proficiency gets a +10% bonus in any case. These bonuses are not cumulative.
An attempt to identify a poison takes one round; be sure to keep track of time elapsed and the onset time of the poison. If one method of identification fails, the next may be tried. If none of the four produce an answer then the poison will remain a mystery to that Assassin. (The Assassin could attempt identification again after he's gained an experience level, but this is not normally of any help.)
Identification of a poison also means knowledge of its antidote (if one exists); it does not mean that the antidote is available, however. An Assassin with herbalism proficiency may attempt to make an antidote from scratch (see special rules, p. 113).[/sblock]
When I think AD&D assassin, I think poison-use. But I also think death attacks, shadow magic, hiding in plain sight, spying, and a bunch of other cool shadowy powers...
Whereas, I want the non-mystical assassin. I don't want the Assassin with Shadow Magic, Hide in Plain. A rogue or fighter with a theme works very well for this.
[sblock=Monk 2e]he principal benefit of being a Fighting-Monk is that the character receives two free weapon proficiency slots which he must use to take Specialization in one of the three styles of Unarmed Combat (Punching, Wrestling, or Martial Arts). These were described in greater detail in The Complete Fighter's Handbook, but that information also appears here, in the "Equipment and Combat" chapter. The Fighting-Monk is the only priest who can specialize in an Unarmed Combat style. He can specialize in any or all of the three styles, but he may only specialize in one of them at first experience level.
As a second benefit, regardless of what it says for the priest's class, the Fighting-Monk has a Nonweapon Proficiency Group Crossover with all five Proficiency Groups (General, Priest, Rogue, Warrior, Wizard). No proficiency he takes will cost double the usual number of slots.
The last of the Fighting-Monk's benefits is this: He doesn't have to spend all his starting Weapon Proficiency slots at first level. He can save his unspent proficiencies, and they do not "go away." Later, he can spend them at a rate of one proficiency per experience level to improve his martial arts or buy new martial arts.[/sblock]
Well, that just screams "Monk" to me; no bonus to AC, no movement, no ki-powers, not even a decent unarmed attack system
While I agree about lack of a decent unarmed combat system, I like my Monk as a priest. THe OA Shaman was one of the few non-core WOTC classes that I allowed and it replaced the PHB monk in my campaigns.
Personally, I want multiple types of monks (I liked the Rolemaster Standard System Martial Arts Companion for this reason)
a. divine monk (think OA Shaman that lacks the spirit companion, can turn undead and has a slightly different spell list). Instead of ki, physical prowess and combat ability is enhanced by divine spells that is combines with unarmed training.
b. a nature based monk that has no turn/rebuke, is attuned to nature, studies the movement of animals, can shapeshift and taps into nature to boost both physical prowess and combat ability
c. a spirit based monk that gains powers from spirits, turn spirits, spirit companion.
d. an arcane monk that knows arcane spells and uses arcana to enhance their abilities
e. a psionic based monk with clairvoyance, telekinesis, etc.
f. a warrior monk better at fighting than the others, versatile in more weapons, strikes vital points, strikes pressure points, dim mak, channel ki to perform feats of strength, agility, quickness, make body hard (protection), heavy (reduce bull rush), light (increased leaping, walk on surfaces with no trace, etc)