- 5e

How do you account for multiclassing power level when compared to a standard character?

Multiclassing creates some weird power balances at various levels of play, mainly because subclasses are incredibly frontloaded and the standard tier of play is tier 2 (levels 5-10). People tend to think of multiclassing as overpower but it's typically because the character is looked at in their final form and not how they progressed.

What exactly do I mean by that?

Most classes gain ASIs or feats at level 4, 8, 12, 16, and 19... so there's a natural progression of power there. Spellcasters also gain spellslots in a similar manner -- typically...

Spells and spellslots follow the same progression but don't always remember that spells are known at class level but spellslots are gained at player level (based on the number of spellcaster levels).

Other significant power increases are levels 5 when most clases multiattack come on and then 11 (and sometimes 17) where features are added to increase the power of the attack action.

What does this mean?

This means there are fairly drastic power bumps at each level but those powers balance out rather quickly. Let's compare my hated Artificer/Wizard with a pure Wizard at various levels.

Level 1: Artificer is probably a little ahead here because the spellslots are the same and they function mostly the same as a wizard. Level 2: Well, the wizard gains their subclass here... so they are probably stronger at this level. Level 3: The artificer caught up and got the wizard subclass. The wizard got access to level 2 spells but the artificer can at least upcast their level 1 spells into their 2nd level spell slot. Probably pretty happy about the multiclass here. Level 4: The artificer gains level 2 spells, the wizard gets an ASI or feat. If the multiclass character is variant human or custom lineage, both characters are probably on the same level here but if the multiclassed character is a different race it's not good for them. Level 5: Sweet, the artificer got caught up and gains their ASI or feat. But... the pure wizard gets Fireball. Feels bad.

The pattern is pretty clear. Multiclassing gives you the advantages of a front-loaded class but delays the progression of your primary class by (in most cases), 1-3 levels. This example was a one-level dip, and two or three level dip means a multiclassed character might not gain accesss to their 9th level spells until 20th level. Meanwhile, their pure class equivalent has been casting Wish since level 17 (three levels earlier).

Why does this matter?

One-shots at a particular static level creates power discrepancies because players can optimize for that exact situation. Level 5 one-shots mean martial characters have multi-attack and you should have a plan if you're playing martial character that multiclassed instead (Booming Blade is an equalizer). Pure Fighters at level 6 have an advantage with their extra feat. But bumping the one-shot up to level 7, 8, or 9 will throw that balance off.

Well, I think there's a few different ways to look at how people play the game. I typically like to "do my thing" as early as possible. This means I value custom lineage and variant human a lot more than other races because the bonus feat lets me get feat combinations like Sentinel/Polearm Master online as early as level 4, where other builds will be delayed to level 6 as a fighter or level 8 as most other classes. Once the "thing" is online, I look at improving it instead of becoming more powerful through higher level features. It means I'd rather upcast a lower level spell than go for those powerful 6th, 7th, 8th, or 9th spells as early as I can; it means I'll probably never cast a spell like Wish unless I play a one-shot at level 17+.

I also have a little bit of a bias for 1/3 spellcasters like Arcane Tricker and Eldritch Knight and because of that, I don't have much interest in spells above 3rd (or maybe 4th) level. That said, it's pretty hard to justify playing an Eldritch Knight before level 11 when the Fighter gets their third attack. Until then, multiclassing with a full caster is probably better -- for example, a Paladin 2 / Warlock 1 / Sorcerer X is better at most levels before 11.

I guess I'm more of a journey than a destination kind of guy. I'd rather have fun playing the game than dream for that big battle at the end where I spent 16 levels waiting for Wish and being happy when I finally get it at level 17 to cast it one time.

Barbarian Multiclassing...

https://www.quora.com/What-is-the-best-way-to-make-a-bearbarian-in-D-D-5E

The best combos with Bearbarian 3 are actually:

    Rogue - Danger Sense and Resistance combos really good with Evasion and Uncanny Dodge. There is no doubt that Bearbarogue is the tankiest build in the entire game and is nigh unkillable. It is vulnerable to mental attacks typically (read: Wisdom save spells) but you want to kill it with damage? Good luck.
    Monk - Monk is not bad and gives you a Bearbarian who has great mobility, lots of attacks, Evasion, and most importantly Stunning Strike, so you can tank for your party and Crowd Control the enemies. Not as tanky as Bearbarogue but not a bad option. Later on Diamond Soul if you get there makes you really hard to kill.
    Paladin - great synergy with Paladin Aura because it shores up your main weakness: mental saves. But practically impossible to do in Point Buy because of how MAD (multiple ability score dependent) it is, so it is hard to fulfill the requisites. But if you rolled a good stat block you can do this and it is probably the actual slipperiest and hardest to beat build in the entire game. Paladin gives you healing (non spell-based) and Saving throw bonus, Bearbarian gives you good life pool and resistance. Match made in heaven, if you have the stats to do it.
    Fighter - Going Fighter is not that recommended, the main point of going Fighter is to reach Extra Attack (2) as quick as possible. But if you are using UA an interesting build is to go Bearbarian 3 then Brute 7. Aside form augmenting your weapon damage dice it gives you an extra 1d6 to all saving throws, which is huge. Further, it means you now have a much better chance of reviving on Death Saves, which makes you a real pain in the ass to deal with.