Level Up (A5E) Why are ability score increases still a class feature?

[noodohs]

I know that's how it is in O5e, but in that case, there are a few classes that get additional increases (fighters, for example). In A5e, as far as I can tell everyone gets increases at the same rate, so they don't really seem to have any reason to be tied to your class levels. When it comes to multiclassing, it has always irked me a bit that you wind up behind the curve on your increases because they are tied to class levels rather than character levels, so I'm just wondering if there's a particular reason to keep it that way. Maybe I just missed some critical aspect of keeping things balanced?

 

[Morrus]

Compatibility, mainly.

 

[noodohs]

Fair enough.