This is why I'm so grateful for Toonami. In its dying days, ASA really only had Bleach with consistent premieres. I remember the days when a show ended, it was not instantly replaced with something new (this is true for classic weekday Toonami as well) the next week. Things would get shifted around constantly going back and forth from starting at 11, then 12, then 1, then back to 12, to "Hey lets so all action" then the next week "Oh never mind lets put some comedy in there". Now we have always have a running block of 6-7 premieres (at least to television) with somewhat consistent ratings.
One thing I read on Programming Insider every week is that AS as a whole is down in viewership from a year ago. This week it was 18% down from a year ago. If you take that into account, Toonami is really not doing bad at all, especially on night when Family Guy can't even crack 1.5 total viewers. Toonami does better on Saturday then most of their originals could do and additional FOX reruns aren't worth the cost on Saturday night, so I think the block is safe for a long while yet. Of course as we've seen before, business priorities change, but I think as long as Lazzo, Demarco, or Manning are at the network, we're in good shape!