Small creatures can't use Heavy Weapons without Disadvantage due to size.
So what is next? A Halfling with an 18 Str is allowed to wield a Great Sword just as well as a 12 Str Goliath?
Or are there scaled down Great Weapons made for little people, that do the same damage as the traditional weapon?
My Halfing Rogue fights occasionally fights two-handed with a Sword Sword and Dagger, because they both qualify as Light Weapons. That should be altered in the rules to only 2 Daggers, because a Short Sword for a Halfling would be the equivalent of a Medium Size creature wielding a Broadsword.
But such immersion into a char and the world the char lives in irritates those that think it is somehow ableist in the real world to impose such restrictions on a creature based on physical limitations in a fantasy world, powergamers hate that kind of thing, and RP'ers who are interested only in the narrative of a campaign can't be bothered with such minutiae.
Is Str done well in 5e? Of course not. We all know there is absolute strength and relative strength. Pound for pound, an ant is one of the strongest creatures on the planet, but it not about to dead lift 8 ounces.
The strongest Halfling in the history of Halflings is simply does not have absolute strength of the average Goliath. It just doesn't. And the only way that can be abstracted with the current rules is by hard species specific ASI's.