I think with the current design, specifically the attribute bonuses given by both race and class, there is scope for penalties. If you get a -1 to the primary attribute for a particular class, such as a charisma penalty for dwarves that would discourage them from playing paladins, then you can offset it with the attribute bonus given by the class itself. The difference in 3E between an 'optimised' race-class combination (ie: half orc fighter) and a 'pessimised' race-class combination (ie: dwarf paladin) was 4 attribute points, which was a +2 difference on checks and such. Now sometimes this doesn't matter that much, it depends how critical your primary attribute is, and in 4E, where it mattered *a lot*, the difference between best and worst case race-class combinations was reduced to 2 attribute points, or +1 on checks and such. 5E has the same range as 4E available at the moment, you can get a stat to 16 or 17 (discounting humans) or leave it at 15, and if you now throw in a penalty, you'll have 14 at worst, or 15 if you want to compensate for that penalty. Now if we look at humans, with their +1 to everything, we actually *do* have a penalty in play, for every other race, of -1 on every ability. Humans can attain an 18 with optimisation, and a 16 without. Any other race only has the range 15-17. Humans suck.
Personally, I'd like to go back to a time when more than just 1-2 attributes matter to you. As a dwarf paladin you'll maybe have a lesser charisma than your human friend (if we change them), but you're tougher, and just as good at hitting things in combat. It should be acceptable to have an attack bonus 1 less than another character, especially in bounded accuracy, in exchange for usefulness in other ways. We need to move away from multiple dump stats per class - don't make dexterity useless if you're going to be heavily armoured, don't penalise martial characters for having intelligence, don't make a single stat responsible for all your attacks, checks, in some cases your AC, and so on.