Mo, I don't think those are empire dresses. Empire drsses are the Jane Austen's style, fitted at the bust and then long and flowing. The skirt starts from the bust, which makes the legs look long and the waist invisible.
Anyways, to answer your question, I do have empire waist dresses and wear them. I would wear them more if they fitted me better, which they don't because I have big boobs, so it's not the best style for me, but I do like the look and don't think it's dated at all. Maxi dresses tend to have empire waists too, imitating the Jane Austen's fashion (Regency Style)
And those two first dresses look AMAZING on you, that red one fits you like a glove, so please don't stop wearing them!!