I understand where you are going, but I simply wont agree. A Goliath being stronger than a Halfing is simply not going to be a problem to me, any more than a Tiger, being stronger than a House Cat is.
But they
aren't necessarily stronger than halflings, are they? A halfling can hit 20 Strength just like a goliath can. And whether you use point-buy stats, or roll-and-assign, or even strict-rolled stats, the gap between a halfling and a goliath will never be more than 4 levels' worth of training (to get the next ASI.) In fact, a fresh-faced level 1 halfling can easily have 5 points higher Strength than a goliath does, a noticeable difference. (I don't know
why you would make a goliath with minimum Strength, but it's entirely doable; perhaps wanting to be a more durable Wizard or something.) And even if you compare a goliath with high strength to one without,
even with rolled stats so a starting 20 is possible, it will
never take more than 3 ASIs to catch up--at which point the halfling and goliath are completely equal purely through training.
And then, from there, natural variability is already a thing that exists. Michael Phelps is physically stronger and hardier than most human beings because his genetics are slightly different (his red blood cells are smaller but more numerous, for example, so his blood is more efficient at carrying in oxygen and nutrients and carrying away waste.) Mozart was an absolute musical
genius who got started at age 5. Gauss was likewise a mathematical genius who (at least apocryphally) was proving meaningful results
in grade school. Meanwhile, some folks have dyscalculia or dyslexia or dyspraxia or a host of things that impede learning, or have physical weakness outside the bounds of normal, or suffer from a congenitally weak constitution, or absolutely chronic foot-in-mouth disease (

), etc., etc. Factors that can easily push someone well outside the "norm" for their physiology.
So...we aren't actually ending up with goliaths who are consistently stronger than halflings, not even when training is accounted for. And there are plenty of reasons why an individual person's physiological/neurological situation might be better or worse than is typical for their species. What, then, is actually gained from having players forced to use these statistics?
I can see the argument that
NPCs should
trend toward these things, because NPCs are generally sampled from the population overall, so there's enough of them for individual quirkiness to be washed out by the masses. I don't see how one can get to requiring that absolutely all PCs strictly adhere to this.
Edit: And your example kinda gives the game away here, doesn't it? You're using something where the difference is not a factor of two or three, but a factor of
one hundred. There is no PC race that weighs 100x as much as another. The
absolute heaviest goliath (~440 lb) weighs only slightly more than 10x as much as the lightest halfling (37 lb.) In a world of magic. Where anyone with 16 Str can have a decent chance to
chokeslam a dragon that is the size of a
literal actual bus.