I was thinking about when some of my characters were half-elves yesterday and I was thinking about why they aren't anymore. (No, looks aren't factor in why they aren't.) I realized that the dilettante feats just don't really offer anything and are kind of expensive, even though they're more or less a "free" feat. (Assuming you're not comparing them to humans, when it's actually the loss of a feat.) The idea I had is this: Why not instead of making only Arcane Archer available to half-elves, change it so that half-elves can get access to a class tree of their choice based upon their dilettante feat. For example, if a half-elf has the cleric dilettante feat, then they could choose to access one of: Divine Disciple, Radiant Servant, or Warpriest trees. This could give some interesting new build options and makes the dilettante feat really do something for the character.
Obviously, the half-elf racial tree would need to be updated, but it really needs an overhaul anyway. So, while they're doing that (whenever they happen to get around to it), it would be "easy" (as in, that's the logical time) to add this in. It shouldn't be over-powered because the player still has to purchase access to the extra tree and they can only choose one. Right now, the dilettante feats are only really useful if you take fighter (for access to all martial weapons), artificer (for the boost to UMD), ranger (for access to bows), and maybe rogue. Most of the rest are not useful (and I know many would argue that even the ones I listed aren't that useful).
Anyway, something to think about. I think it would add a great deal of character building options. (It would be nice to be able to learn other races' dances, too, because humans suck at dancing and it's kind of fun watching a half-elf Ken doll do the splits.)