Evans and Martin don't really give anything else outside of rebounding.
Odom's defense>>>>>>Evan's defense. His offense is also better now that he is getting back into shape, he can hit Fts, and he has great passing ability. Evans is just a rebounding specialist.
Barnes is infinitely better than KMart offensively so yea overall its a huge upgrade and it shows.
There is a reason no one has picked KMart up.