Romance is very tricky, as obviously there's plenty of it in the game already. But I like stories about a sort of unspoken attraction, so it would be nice to have a way for Sims to be attracted to each other that isn't either a) they full on make a move on each other, or b) they smelt the right candle so they're ready to flirt with anyone. Even for the flirting in-game, I'd like something more subtle than openly blowing kisses at each other. An attraction system, so Sims can be attracted or repulsed based on personality or looks, or even just a set of romantic activities that might give people a romantic sentiment, would go some way towards doing that. Hopefully a Romantic Getaway pack is coming, but we'll see!