A "Toonami" block on Boomerang would work. Considering that the block is ten years old and has established itself as a marketable brand in its decade of action, it would be a welcome breath of fresh air on Boomerang, which has maintained the same appearance it had since day one, and strangely more modern shows.
Of course, one would have to wonder what they could put on the Boomerang "Toonami" block. It'd be easy to bring back Moltar to host the new block considering they still have the master tapes and many of the people behind Toonami are still employed by The Network. Also, quite a number of Toonami shows are either in the Boomerang/CN library or currently airing on the lineup including the following Toonami vets:
Thundercats
Voltron (that's why they were able to show Voltron clips in the montages during the 10th anniversary)
The Real Adventures of Jonny Quest
Batman
Superman
Batman Beyond
Samurai Jack
Justice League
Megas XLR
Masters of the Universe
G-Force
However, it'd be foolish to say that Boomerang's Toonami block would air the Japanese shows many people believe Toonami is all about. Perhaps they could get the original incarnations of Dragon Ball Z (namely the first two syndicated seasons) and maybe Robotech, but there's no way they'd get Gundam, Outlaw Star, or any other marquee Toonami brand of the past, and that's what Boomerang is (supposed to be) all about.
Should they create a Toonami-branded retro action block on Boomerang? Of course. Will they? I doubt it, but stranger things have happened.