I have a feeling that we might not get 10 bans until next preseason.
Remember Ao Shin, Solo Que, Replays, Sanbox Mode, the scrapped Yorick Rework from 2012, a better tutorial, the comeback of the Tribunal . . . ? These are just a few examples.
Riot has a tendency to announce things and not give us anything until much later and then give us an official statement that it won't come after all or be late like 1-4 years or so. Sometimes they don't even give us a statement in the first place to avoid negative backlash or because they hope that most of us will forget about it over time.
Any promise Riot makes at this point is highly unreliable so don't get your hopes up. We might get it pretty soontm but I think it's more likely that we won't hear anything from Riot's side until much later.