This.
As far as mechanics are concerned, the nonhumans in D&D (at least, the PHB nonhumans) have been humans in funny suits for five editions now. They got a handful of odd little tricks, and some dinky modifiers that didn't take you out of the human-normal range unless you rolled incredibly well or incredibly badly on stats, and some class and level limits that only mattered at chargen or at levels you were unlikely to ever reach. And that was it.
There was only one edition where nonhumans played really differently from humans, and that was BD&D/BECMI, where "dwarf," "elf," and "halfling" were classes with their own rules. I don't say D&D needs to go back to species-as-class, that brings its own problems, but I would like species where the impact is comparable -- where the mechanics pull you into the mindset of a being built on different biological/mystical rules from humans.
But I don't see that happening in 1D&D, and certainly not in the core books. Like it or not, there is a big market for humans in funny suits. Fixed ability mods do nothing to change this, never have; meanwhile, they impose a modest but unalterable penalty on many character concepts that would otherwise work fine.