It's an interesting balancing act - making those who are "proficient" better than those who are not, without making the the non-proficient totally useless (or to allow the proficient challenged by something, without making it impossible for the non-proficient). Is +30% (ignoring attributes and dice tweaking class features) enough of a gain to be distinctive? Arguably, this is what the stat boost is supposed to be doing: you are effectively getting +1 to all your X-based rolls, proficient or not.
Something I find interesting is that they are shifting bonus inflation into the probability game. Fighters don't get huge to-hit bonuses, they get more at-bats: More tries improves your chances of making a hit, and better damage through multiple hits. And then there's the whole Advantage/Disadvantage element to mess with things.