I've had dancers express to me their disinterest in hearing the caller's voice at the end of the dance, regardless of how mellifluous that voice is - their point was that the music told them the dance was ending. They didn't need a caller to do that. So (in my very limited experience) I choose to do so only sparingly, where it adds value.
As a dancer, I value a caller changing the dance when it fixes a problem with the ending. For instance, when the transition is at the end of the dance, having the music end with me giving my hand to a new N (whom I just get to share a smile with and then turn to my partner for the real "thank you") is awkward. Changing the B to make it end with my P adds value there. If the dance is otherwise naturally "interesting" at the end, then modifying it is less valued IMO. And if a caller does change the dance, making the mods unique adds variety. If every dance ends with a variant of "keep swinging"...
