(Assuming D&D 5E here)

I wonder what the best way to go about it would be? It can’t just work the same way as regular multiclassing since you’d effectively get no base class features for your second subclass

Pretty simple, just treat it like spellcaster multiclassing. Wizard/sorcerer/cleric/ 1/1/1 translates to a level 3 spellcaster for the sake of spell slots. Rogue 3/3 translates to class features level 6 and archetype feature level 3/3

I bet some obsessive nerd has converted DND to point buy (like wod, gurps, etc) instead of class and level based.

You get XP for stuff, and you can spend that as you like on all the stuff you’d get from leveling. Follow the recommended route and get a standard looking fighter. Or go crazy and buy nothing but hit dice. Or make a glass cannon by buying all the sneak attack dice and second attack (in case you miss) and nothing else.

Or, per this meme, buy superiority dice and maneuvers, and then also buy extended crit from champion.

It would be a mess. I think part of why dnd is popular is its comparably small decision space. There’s just not a lot of room to fuck up your character

That doesn’t work.

A Spellcaster multiclassing always gets something on level up, be it a feature, more spell slots, or higher level slots.

A rogue multiclassing into rogue and splitting the levels would have dead levels at each subclass level.

To explain what I mean: a Rogue gets its subclass features at 3rd, 9th, 13th and 17th level. By going with your math, a 9th level rogue would classify as a 4/4 rogue (by rounding down) as far as the subclass is concerned, which means that the rogue gets nothing at 9th level.
Not only that. A 50/50 split for the multiclass progression would imply that a multiclassed rogue is precluded from getting any subclass feature higher than the 9th level one. By comparison, a Wizard/Sorcerer/Cleric multiclassed character can absolutely attain 9th level spell slots (although not 9th level spells, confusingly enough).

The short answer is the game wasn’t balanced around it.

I feel like Rogues (sneak attack) and Wizards (spell sculpting) in particular could abuse this heavily. Also any class that gets their subclass at level 1 or 2.

This is the anwer. You could always homebrew your own game and try to balance it, and you’d start to find where the game breaks. Play 10,000 games like that, and patterns will emerge. Game developers spend a lot of time playtesting, and they still miss things. Just thinking of a new twist and asking why it doesn’t work is like asking why cars don’t have six wheels.

That still sounds balanced-ish. If anything, it’s too front-loaded. A 9th level rogue would still have its typical kit of sneakiness, skill proficiencies, and sneak attack at 9th level, but it wouldn’t have a 9th level bump via archetype because it received a 6th level bump via archetype.

A more typical example- a level 3 fighter/level 2 paladin wouldn’t get a second attack despite being a level 5 martial character, and they have to live with that mechanically poor decision. But they can instead choose to play until they become a level 5 fighter and then branch out instead, if they care to min/max.

And what gives you the impression it has to be 50/50? A sportsman can be great at throwing or hitting a ball, but it’s vastly different between one sport and another. You can be an incredible baseball pitcher and a garbage basketball player. Level 3 arcane trickster/level 17 assassin makes perfect sense to me.

Level 3 arcane trickster/level 17 assassin makes perfect sense to me.

That’s not a multiclass as intended in 5e rules. That’s just a 20th level rogue that got all the features from one subclass and the first feature of a second subclass for free.

I’m gonna respect to 1/1/1/1/1 fighter/fighter/fighter/fighter/fighter so I can action surge 5 times in a round.

If you know anyone who has actually reached 20th level in a campaign, it might make a difference. I’ll put you in my will if I hit the lottery.

Warlock: I promised my soul in exchange for great power.

Rogue: To which great power?

Warlock: All of them. Let them fight over it when I am dead.

Or just play one of those systems. GURPS is great.

Yeah, I mostly play Fate or nWoD. But a lot of people are really emotionally invested in D&D, so sometimes I think of ways to try to trick them into playing something different while they think they’re still playing D&D.

Because 5e is a simple game made for adolescents. It’s easy to pick up, easy to build a character, and easy to run. The problem is once you start trying to do anything particularly interesting, it crumbles. It foists basically all mechanic decisions that aren’t directly related to combat onto DM adjudication, and provides very little guidance. I mean, last I checked you have the option to be proficient with various sets of craft tools, but the system doesn’t actually explain what that actually does mechanically.

If you want to make interesting character builds, you have to transition to a more detailed system. I’m partial to GURPS myself, but Pathfinder 2e is a nice middle ground of detail while still being fairly familiar to someone used to D&D.

Thought: Homebrew where you pick two subclasses instead of one and both evolve normally. No multiclasses cause it’d be kinda nuts as is

It foists basically all mechanic decisions that aren’t directly related to combat onto DM adjudication, and provides very little guidance.

The idea here is that the D&D ruleset is supposed to be permissive, not restrictive:

• permissive - anything not explicitly prohibited is allowed
• restrictive - anything not explicitly allowed is prohibited

The gameplay experience depends greatly on which of these directions you interpret rules from. So, when you say that it “provides very little guidance”, that’s intentional, because it allows the DM and the players to use the basic structure of the game to support and inspire having fun and being creative. It should be a foundation, not a cage.

D&D was always intended to be an open framework for actual roleplaying. The munchkin concept of gaming the rules for min-maxing stats came later.

Rules lawyers, be they DM or player, make playing less fun.

No, the idea is that 4e basically imploded the brand, so they pushed some unfinished stuff out the door before the axe came down and suddenly and unexpectedly they discovered that the brand was printing money.

Rules aren’t restrictive, because every rule is optional. A lack of guidance is WotC asking you to do their work for them.

The game isn’t balanced around multiclassing, either. If it were, everyone and there dog wouldn’t have difficult to explain backgrounds that involve blood magic, mysterious patrons, and devout faith in something.

Also any class that gets their subclass at level 1 or 2.

To be fair those are also troublesome for regular multiclassing, or at least they are if you’re not using the 2024 “definitely not 5.5E” classes. The paladin with one level in warlock or sorcerer is a perennial favourite for a reason.

I suppose an approach that takes the general intention of your design but is a bit omre mechanically rigorous could be to separate out subclass levels? You level up in one class as always, and every few levels the thing you get on levelling up is a subclass level. Subclasses then only get four or so levels, so you could be a warlock 11 (archfey 1 / fiend 2)