More about features like Powerful Build and Half Elf Versatility.
What about a fast species that just has a base speed of 40ft? Or a species with eyes so fine, their ranged attacks increase by 20 ft.
So it is bad that they didn't design something they didn't design? Sure, you could make those things. Just because they didn't, or they didn't design a species with four arms or a species with skin so thick they have a natural armor class doesn't mean they have done anything wrong.
Or give species skills. Not from culture but biology. Maybe gnomes could be so naturally smart they all get proficiency with a lore skill. Or Halfling fingers being delicate to the point that they all are proficient in Sleight of Hand?
Sure, they could do that. But, um.... they also DID give species skills.
Humans get a skill
Elves get a skill
In the playtest, Halflings get a skill (stealth) from Naturally Stealthy, which they still get in 2024. And likely still get to replace the old ability of hiding behind people. Which, interesting note, would show that both exceptions to the stealth rules from the species got cleaned up. Could be part of reworking the stealth system into... actually functioning better.
Sure, that is only three of the ten species that get a skill... but do they need to give EVERY SINGLE species a skill? Can't the species have different designs?
Why did orcs lose Powerful Build?
Likely to open up the power budget to allow for their Temp Hp ability to recharge on a short rest, since that is fairly powerful upgrade.
Why did goliaths lose Athletics?
Likely because it was meant to represent Goliaths being better able to grapple and break out of grapples, and now that grapple is no longer an Athletics check, it isn't serving that function anymore. Instead, they added specific rules to showcase the Goliath ability to break out of grapples.
Who is the diplomat species?
Whoever it makes sense for? What an utterly bizarre question.