As cool as it is to see Toonami come back, I don't see it lasting very long. I've come to learn that anime fans are pretty impatient people and they don't enjoy the wait between episodes and in a world where we can get most anime at our fingertips; what's stoping people from going online and watching the next episodes and just skipping the tv versions? Sure nostalgia will get people to tune in weekly, but nostalgia is kinda finite. And at a late time slot, I could see people begin to tune out.
I will say though that it could be a way for new viewers to catch some cool shows and it makes more anime fans (especially if they play Bebop), Tom coming back would be awesome, and if they have marathons of shows and movies (like mecha or Miyazaki months as they have in the past)
Of course, I've never watched Toonami being Canadian and never getting CN, so I could be talking out of my ass on this one.