When critiquing Morris is easy to forget that this is the defense that McVay wants.
McVay dumped Wade's scheme and brought in Staley because he wanted the Fangio defense. He brought in Morris, who had no history with the Fangio defense, and they continued to run the Fangio defense. Not saying Morris can't run it, but one has to wonder if this is the defense he would run if given the choice.
This is the defense McVay wants because this is the defense that McVay hates facing. Just as Fisher played dink & dunk offense because as an aggresive defensive coach he hated that it took away his ability to rush the passer, McVay, as an offensive guy, chose a defense that fustrates his big plays.
I do think Morris could probably be more creative in implementing this defense, but to lay the faults of the defense purely at his feet is to avoid the fact that Morris runs it because McVay wants him to.