I also thought this was the best episode yet. I'm not quite sure what to make of the "creepy old man" accusations. Obviously, the Frasier exhibited poor judgment in his enthusiasm over both women. However, while both of them were attractive, Frasier's attitude towards them seemed to be based not just on that, but on some pretty solid signs of compatible interests with each of them.
Also, KG is 68 (per imdb), and the actress playing Siobhan apparently is 57, which is not that dramatic an age difference. I wasn't familiar with the actress playing June, but see that she's listed as 43 years old, which is a more significant difference. However, I took her to be in her 50s. (That's not meant as a negative. She's an attractive woman, but I think that she was styled -- probably intentionally -- in a way that made her seem a bit older to make it plausible that someone would set her up with Frasier.)