I agree that Larian should keep the current heads but add some new ones that look like proper, otherworldly elves (and half-elves). That way they don't have to scrap any of the currently advertised companion designs like Astarion and Shadowheart. At the same time, they'll also please more discerning fans. The more human-like heads I can just pretend are elves with a bit of human ancestry or something.
Shadowheart wouldn't need to change, half elves will have as much from their human side as their elven, often more. Means Half Elves can be super diverse, getting features from both ancestries. Asterion wouldn't need a massive change, he's already more slender and angular in features than almost all the currently available elf heads. minor tweaks to perhaps his eye shape and jawline would probably have him sorted.