However, not having to rely on certain races for classes would be great.
You'll be delighted to hear that this is 5e. You can pick any class as any race! Have fun.
Results in weak, suboptimal builds.
While I agree in the strictest sense that lacking (at most) a +1 to an ability modifier is suboptimal, you really need to consider the difference between suboptimal and optimal. You clearly value a very minor increase over roleplay, so just embrace the min/max.
The notion that you have to "rely" on certain races for classes is just flat out wrong, though.
What race/class combos are you thinking of that are so tightly intertwined that you'd describe them that way?
