Have you thought about re-skinning the cut races into the added races? On the other hand, are people going to bothered if trance was taken out of the elven racial kit? It has rarely, if ever come up in campaigns I have been in, but your experience may be different. Even the immunity to magical sleep is only useful against a very specific magical effect (though it could probably be left in anyway as the half-elf needs sleep yet is still immune to magical sleep). On the third hand, could half-elves be re-skinned as elves? I understand the desire to maintain verisimilitude, but cutting two PHB races because of one racial ability that one of them has seems excessive. Disclaimer: There may be more reasons for this choice and I don’t want to assume, but they weren’t mentioned in the article so I am commenting on what was.