The existing elven heads are pretty...I wouldn't debate that... but there's nothing to distinguish them from half elven or human heads aside from ear shape. You could put all of the elven, human, and half-elf heads into the same pool and nobody would be able to tell which is which. Some minor changes, particularly to eye size and shape would go a long way towards making elven faces not interchangeable with half elves.
Maybe Female Elf heads 3 through 5, but 1 and 2 are god awful. 3 through 5 could use more angular look. Similarly, the male Elves look more like what would be male Half-Elves and vice versa (the male Half-Elves look like male Elves). Elves should have more angular faces which is what people have been arguing.
It's all a matter of taste, isn't it? I think female elf heads 1 & 2 are the most elfy. I used female head 1 for my high elf wizard and was very happy with it, and am pondering head 2 for a female wood elf, as while I like head 4 better in many ways it just doesn't say "elf" to me.
And I do see the the male half-elves as more human-looking than the elves (and on average prettier, but as they're the ones with +2 charisma I don't see a problem with that ).
Hopefully Larian will add some more choice, and where a face could potentially work for more than one race they'll make some small tweaks and make it more widely available. They've clearly already done this with a number of heads, though some are more successful than others.
"You may call it 'nonsense' if you like, but I've heard nonsense, compared with which that would be as sensible as a dictionary!"
). 
