I always kinda suspected they were going to do this due to the movie coming out. Since they own the show, it costs them nothing to air this and ratings won't be too much of a concern, but I still think it might grab some people who haven't seen it before/ want to see it again. Funny I LITERALLY just watched both seasons last month! Second time this has happened, first time was with Champloo last year!
I firmly believe that the block will get 11:00 PM for Jack and Titan (the only way that doesn't show up is if FUNimation isn't offering it and wants it to stream it themselves). Then later in the year, there's going to be FLCL and I believe they've already stated they'd like to rerun the first one before the second one shows up. It's entirely possible that at some point this year (may not last forever depending on the need), Toonami may run the full 11:00 PM to 4:00 AM. Jason hinted at the possibility of a few shorter shows coming to the block as well and I just don't see them able to do these things unless they expand further. Jojo could also take a break before going into Stardust Crusaders (in fact that's what Jason thinks they are probably going to do as stated on his now defunct Ask.Fm). I like the idea of other nights as well if they feel its worth their while. I think we are in an era where Toonami will be whatever the situation demands of the current show slate. Of course, the numbers will guide the way and adjustments will be made to ensure the block's survival. As long as Demarco, Lazzo, and Manning are around, I have a feeling so will Toonami!