Clunky

Gygax, for all his marketing and conceptual genius when creating D&D, really wasn't very good at creating elegant rule systems. I'm at the stage of Treasures, Serpents, & Ruins (TSR) where I think if I put this out, it will either be a generic rule set or a specifically kitchen sink Asian fantasy inspired rule set. Either way, I'd like a system for multiclassing, but 1E AD&D is just such a mess that I think I need to look elsewhere.

First of all, AD&D has the weirdness of demihumans multiclassing (fairly straightforward, but with lots of corner cases and provisos depending on which two classes are being combined, and limits on what can be combined) PLUS human dual classing (a bit more complex with required ability scores, limits on what powers you can use and when, etc). Why two completely different systems? Obviously Gary wanted distinctions between humans and non-humans. Also, allowing carte blanch demi-human style multiclassing could create some unbalanced nightmares (Paladin/Rangers? Cleric/Fighter/Magic-Users with no level limits on them?).

At first, I was thinking to just allow humans to multiclass, but with level limits. I even considered removing level limits from single-class demi-humans, so level limits are only a check on multiclassed characters. Multiclassing though a bit easier than dual classing, still has some headaches. Especially with energy drain. If you get level drained, which class's level gets drained first? If you maxed out one of the two classes, but have still been accumulating XP in it, and it gets drained, that's a huge chunk of XP removed! Although it probably won't matter much, if you go from Fighter 4/Thief 8 to Fighter 3/Thief 7 with a double energy drain. You'll probably make that Fighter level up pretty quickly. 

But to get to the point. I want a more elegant system for TSR (or TSR-East, whichever). My current version of TSR has premade classes that combine two base classes. A few of them are pretty popular. The Lark (Fighter/Magic-User) has seen a lot of play [four PCs]. Next most seen is the Paladin (Cleric/Fighter) [2 PCs]. Finally, we've had one Warlock (Magic-User/Thief) in the campaign. Assassin (Fighter/Thief), Bard (Cleric/Magic-User) and Darkstalker (Cleric/Thief) have been ignored so far. 

In service of a more elegant rule system than one with 10 character classes, of which 4 of them each come with 4 subclasses for a total of 26 options BEFORE considering character's race, I want to strip things down to the five core classes of my current TSR-East rules: Cleric, Fighter, Magic-User, Thief, Xia. No subclasses. 

Then, with these five classes, we can have 10 multiclass combinations. But these don't need to be separate classes the way they are now in my main TSR rules (the house rules for my West Marches campaign). 

I plan to simply create an XP progression chart and hit die for each combination. I'll have none of this dividing XP in half and leveling up separately of 1E, and halving hit points rolled at each level. Like the Elf of BX and BECMI, it will have all the powers of both classes, which level up at a certain rate. Attacks and saves will be done by whichever class is better. 

For example: A Fighter/Xia (kensei style)

The PC could use any armor (fighter), or go unarmored with level-based dodging (xia). They could use any weapon (both classes), but could also do better unarmed damage (xia). As they level up, they could sweep (1 attack/level vs 1HD opponents), get a combat style, multiple attacks, and a smash maneuver as a Fighter (if they are allowed to get high enough level). They also get all the monk-like abilities of the Xia like improved jumping ability, stunning fist, various resistances, and so on. 

Since the Fighter needs 2000 XP to level 2, and the Xia needs 2200 XP, just add them together. The multiclass Fighter/Xia would gain level 2 when they have 4200 XP. Since I give Fighters a d10 hit die and the Xia has a d8 hit die, I'd give the multiclass the d8. The Xia has slightly better saving throws, so use those. Base attack bonuses are the same. 

Example Number 2: A Cleric/Magic-User

This PC could wear any armor, use blunt weapons plus daggers, cast both Cleric and MU spells, and turn undead.  They would get a d6 hit die (average of Cleric d8 and MU d4), and would need 4000 XP to reach level 2 (1500 XP from Cleric, 2500 XP from MU). Cleric generally has better saving throws, so use them for all categories but Paralysis/Turn to Stone, which would use the MU save until 5th level when the Cleric save gets better. They'd also use the Cleric BAB progression. 

This seems like it should work. The only thing I need to consider now would be level limits for the combinations. Would different races get different limits? Would humans also be limited in this way? That would be a pretty big change, but I think in general this is a much more elegant way to handle things. And then I don't need BX-ified versions of the Paladin, Ranger, Illusionist, let alone Sohei, Ninja (1E OA style), or Kensei. 

It also eliminates the need for subclasses which also fill in archetypes like the above. Want healing magic and undead turning but better fighting ability? No need to have Paladin AND Sohei classes. Just play a Cleric/Fighter and style it as one of those...or a Vampire Hunter, Templar Knight, or whatever.