The PHB is fairly vague on when you get ability score improvements and/or feats - specifcally as it pertains to multiclass characters. Is it based on Total Character Level or is it earned independantly by class level?
I am playing a wizard/warlock who may also multiclass into bard. Hes a very fun and interesting character to play, with a nice backstory - but i went get ninto that so much. just suffice it to say that wiz/war/bar fits him very well.
We're level 4 now, (I am wiz-2/war-2) so everyone else is picking feats or improving their ability scores. When i first multiclassed at second level, me and the DM talked about the ability score bonus/feat issue and we both originally thought it was based on total level, like proficiency bonus. But unlike prof bonus, it isn't specifically addressed in the multiclass section. And then another player pointed out taht unlike proficiency bonuses, not all classes abilityscore/feat progression is at the same rate. The fighter gets two extra, at levels 6 and 14 (I think.)
MY houserule suggestion is that its based on total character level, but a multiclass fighter will still earn teh extra one at fighter level 6 and again at fighter level 14. Everyone agrees that seems balanced and logical, But I wanted to check the forums here and see what the community in general thought. I'm sure we've all been there where we houserule something thinking it was balanced but then in play realized it wasnt.
In my honest opinion multiclassing is already disadvantaged by being spread thin. Their versatility somewhat makes up for it, as well as some minor synergies with different class abilities. But even still, I think that if you could quantify it, they are at a disadvantage. A fighter-5/rogue-5 can do fighter things or rogue things, but they are all level 5 things, and he's still only one character with one turn. If the feat and ability scores are based on class level, then thats a significant delay for multiclass characters. If you you multiclassed evenly in two different classes, you'd be character level 7 before getting your first bonus. You'd catch up when you got your second bonus with your next level, but I dont think that makes up for being behind for 3 levels. Another wrinkle is if you didnt want to progress evelnly with your multiclassing, you could get to max level 20 and never get your final 5th bonus - for example if you were fighter-3/rogue-17. You'd have to keep all your class levels in multiples of 4 to get all 5 bonuses.
NuclearSunset wrote:
It's easy to miss, but it's not just fighters who have more than five Ability Score Improvements - rogues get six.
But yes, it's linked to class level, just like any other class feature. At least every ASI can be used on any ability score you want, so you could advance to, say, Wizard 4 and improve Charisma by 2 if you wanted.
Hm.. 
ok then... I dont mind houseruling something under the assumption that it was overlooked or unclear, but from what you guys have said it seems that the general consensus is that this is an accepted drawback for multiclassing. i'd still like for him to get into bard... maybe I'll plan for wizard 4, bard 4, and warlock 12. BTW thank you guys for the input ;)
Its more a 'drawback' for taking small dips. Grab 4 levels and you get your ASI just fine, but go only 2 for some front loaded benefit, and you lose out a bit.
it's not just a general "concensus" if you look at the 15 in the PHB (the table showing the Experience point needed to reach next level you also get your profiency progression. Then within the multicalss section, they say that your profiency bonus is based on character level.
ASI are a class feature that your class obtain when he reach level 4, 8, 12, 16, 18 (fighter and rogue are an exception) it's not a rule of thumb that you gain a ASI avery 4 level.
unless stated in the Multicalss section, your multiclass do not interact between each other. and many ability overlap (instead of stacking)
Multiclassing do not grant the level 1 bonus like save profiency of the multiclass stat, do not gain aditional skill (unless stated in the Multicalss section) and do not gain weapon/armor profiency (unless stated in the multiclass section) (but the armor/weapon profiency gain from the cleric domain or valor bard are also received when multiclassing, but those are class feature that you gain at a certain level, not 1st level profiency bonuses.