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"...