Capable of driving three 4k video signals. Amazing. Why can't the new Mac Book Pro drive just one?
I would characterize it as the absolute bare minimum to even be in this space.
I have 5 monitors attached to my 2009 pro (3x 2560x1600 main displays, a 1920x1200 offset on the wall, and a 1920x1080 "tv" cabled out to another room) and I've considered adding a sixth.
It's hard to say how many <4k displays you can add to the ports on the back in addition to the three primary 4k displays, but it had better be more than "zero".
;)
And three (insert current high end display circa this year) monitors attached to this new mac pro will also not be amazing.
What will be amazing is if you can't add a 4th, 5th and 6th - of any resolution.