So M19 looks like it's gonna be Ajani finding old friends, as well as a reminder that Tezz and Lil are batting for Mr. Immortal Bastard, and then the Ravnica block to end all Ravnica blocks. Possibly literally.
Erm, Channel did not show up exclusively on Spirits with ETB abilities. In fact, none of the cards it showed up on had ETB abilities. The majority of Channel effects were stronger versions of Activated abilities the creatures had, and the others granted some sort of keyword, like Fear or Haste.
It's gonna be a good year.
http://gatherer.wizards.com/Pages/Search/Default.aspx?action=advanced&text= [Channel]&set=+[%22Saviors%20of%20Kamigawa%22]