I think it is really dumb.
With the exception of Laezel and Astarion (and even there only the vampirespawn modification), race is far less essential to who they are then their class is.

Gale as a gnome or a dwarf or a tiefling would still be more or less Gale.

Gale as a Barbarian is just a completely different character. What even is his backstory now?
He wants to impress Mystra, and so he hits people with an axe really angrily?

Wyll is a human. But what would change if he was an half elf? Nothing!
But what if he was a Paladin?

And yes, yes, you can stay "what if he was a Paladin who still had a pact with Mizora".
BUT NO! That is what being a warlock is. You can not be a pure Paladin and still be defined by the warlock pact you have with a devil. It is just nonsensical and completely breaks the story.

So no, I think customization is great, but we have the hirelings for a reason...