Don't waste yer bans in Normals...
on the new champ when the champ isn't overpowered.
For on-release monsters like Yasuo, it's reasonable. But Taliyah is balanced and not too hard to play around. Save your ban for Ekko, Soraka, Zed, and the like.
All it really does is open up an overpowered pick, and prevent someone who was excited to try her from getting to play her yet again.