I admit I wasn't sure my newish classic rock cover band would go for Wonderful Tonight. But my vocal range is similar to EC's, and we have very good keys and LG.
It consistently fills the dance floor! Placement may have a lot to do with this, and slow dances in general. We do it mid to late Set 2. Any earlier and the guys aren't drunk/motivated enough to dance. Any later and you run the risk of few people hearing it.
We just did "Something" for the 2nd time. Took me a while to get the vocal and bass parts down, but feedback made it all worthwhile.
We recently did "Creep" and that worked. Easy as heck to learn, except guitarist still having trouble timing the "false start power chords" just before the chorus, and drummer not entirely sure of the ending. In fairness, we tried it at the rehearsal that was 2 days from when we thought our LS was a no go, and we were scrambling for songs. I convinced/begged them to do it even though LS's laryngitis cleared up. Looking forward to bringing it back.
Used to do "Travelin' Man" (Ricky Nelson). Not a bona fide slow dance in my mind, but crowd always used it as such. It's mostly about the harmony vocals, assuming the lead vox is competent.