Director Chris Columbus, who is executive producing Gremlins 3 and writing the sequel, did not particularly enjoy the second movie.
It is almost impossible to imagine a world where Gremlins 3 gets made and they actually kill Gizmo.
Speaking of Gizmo, Chris Columbus also talked a bit about the approach to the movie and explained that CGI would only be used to help out the puppeteers.
As it stands, Warner Bros. controls the Gremlins franchise and it is up to them to make Gremlins 3 happen.