I don't know. Chaos sorceros is such a mainstay for twilight decks, anything tha uses both light and dark...It will be gone on March...Thoughts on how to fill the void made by our favourite spellcaster's dissapearance into the void?

Even at 1, Chaos Sorcerer can still be used. After all, it survived the last time. It's not just Chaos Sorcerer, however, but other things that got hit that could end up putting it in trouble like Charge of the Light Brigade and whatnot.

So what will happen to Twilight? Less of it? More Dark/Light pures?

There's no way to really predict right now. We'll just have to wait until the new format official begins for tournaments.