I think they took off immediately. I mean, even before they knew technically that they were going to be a block again. The April Fools' stunt really was them hitting the ground running. And they really had a pretty clear blueprint of what Toonami was and what they wanted it to be. Certain shows have been hit or miss. But the block basically hit the ground running and really hasn't faltered much as a whole.
The worse thing was probably running low on domestic programming and having to scale the block back, which in the long run really doesn't seem to have hurt the block or the fans.
I have personal ideas of stuff I would like to see them do and quibbles here and there about "more of this - less of that" but overall, the block has been pretty consistently successful and I enjoy almost all the shows they've picked on some level or other.
The danger for Adult Swim right now is complacency and resting on the comfy cushions of mainstream Fox shows. Toonami, even at its most commercial/mainstream, is still something of a counterbalance to that. Which I think is something of a blessing and a curse for Toonami programmers.
Ultimately I would like to see a Toonami that remains alert to good stuff. I don't mind the necessity of mainstream stuff, I think it would serve the block to continue to occasionally drop in adult material, odd things, and an occasional nostalgic pickup.
It serves the block well to stick to that path of mainstream long runners and proven/popular new shows (especially if they can get good deals on those). But I also hope there is space to throw bones to mature sensibilities, those seeking something different, and maybe that occasional bit of nostalgia.
If they can keep a toe in those waters as they forge a solid schedule of new/proven shows chosen with the Toonami audience in mind, I see no reason the well should ever run dry (at least for the forseeable future).