I was a little sad to see J'onn taken out of the founding roster, yeah. There were things that bothered me a lot more though. Booster Gold for one. Wally West for another. And really, Cyborg earned his place with the League. Its still a bit weird seeing a long standing Titan there, but Vic deserves his shot and I hope that before long he is considered A-list.
And I do miss the sweet, kind hearted J'onn who ate too many cookies and rolled his eyes at Booster and Beetle, and held his own next to the most powerful beings alive. But I am really curious about what he's up to now. J'onn might not be in the League, but I feel like more is being done with him now than has been for ages. Its all subplots and questions and conjecture at this point, but when things finally shake out and the Daemonite stuff comes to a boil, I am fairly sure J'onn will be at the heart of it.