Looks solid to me.

What kind of robot are you building? That is a lot of parts! heavy duty

You will need some heavy gauge cable from the 2 12v 12Ah batteries to Sabretooth controllers and similar cables to the motors other than that its fine and won't need a grounding bar if you use the correct amperage cable. Possibly a 5A or 10A fuse in each feed to the motors to protect the Sabretooth from a motor stall current although they should have protection built in. If that fails you need a backup!

As I have said before on these forums think safety kill switch with this sort of setup

;)

Yea , you need a main fuse Positive from batt supply , then any positive feeds.from ez b need a fuse. Don't worry about fusing between motor and controller because even a little resistance will cause amps to spike and blow a fuse , you will pop them all the time (unless you add a fuse well above the motors rating which negates the point of a fuse). Definantly fuse each pos source to your controllers that way it will only pop a fuse when it exceeds the controller capabilities.