I just have to say...wow.
A) They smack up the Arbiter with the newly added activated ability to cloak all nearby units AND buildings. I'd guess this makes the Mothership stationary during the field's maintenance. Still, wow.
B) Time Bomb now appears to be triggered at a particular point, with a smaller radius and the trait of slowing/stopping all ENEMY missile attacks while allowing your own to penetrate unhindered. Just groovy.
C) Planet Cracker has been dumbed down, clearly causing less damage but still a substantial amount. The action shot of two Motherships turning a Command Center and its defenders into Swiss cheese is awesome.
D) With the lowered power of the Mothership, having multiples is hardcore, as the ship is still amazing. It HAS to have a weakness...even if it's simply outstanding resource requirements or build time...