Barbosa's scoring, Barnes wing defense and occasional offensive input, Boguts rim protection, Ezelis defense, Speights scoring

You're kidding me if you believe all that is easily replaced. Pachulia & David West are the only acquisitions who will make any kind of difference.
And your belief in Durants defense is questionable as well. Here's a superstar who people trust will be this great defender and he's yet to even make an NBA All Defensive team. So I would pause on that sentiment until proven otherwise. He plays D in spurts but not consistently.
The Warriors lack of depth will ultimately be their downfall.