Wrongly deleted people cannot then be found and likely lost forever or until created again.
Using search I found person A created by familysearch from baptism records with no changes, this person I recognized and placed on my tree unchanged. (I now realize I should have added further details and "followed" this person at this point, but I am a new user.)
Another user made WRONG changes to birth, baptism, parents, and sources of person A.
This user then WRONGLY MERGED the person A with another person B, same birth year, father's name and parish, but separately identified in parish and census records, easily done.
This caused the modifed person A to be deleted.
The original person A will be now be lost and not found by search - remember the deleted person A (if still held in your system) now has the wrong birth, baptism and parents and source details. (By pure luck I saw this error as they had an erroneous photo, and I was able to restore person A and I believe rectify all the wrong changes to details.)
If I had not restored them, the original and truly existing Person A would be lost forever to anyone searching fresh. I believe this has happened a lot as I seem to need to create many people whom I am sure familysearch would have found earlier.
I suggest that, if a person is deleted then all changes made before deletion should be reversed and that person restored so others can find them.
Perhaps just all changes made by the user doing the delete should be reversed and then the person restored.