It's an effect that is so powerful but so generic that it can fit in almost any deck
Renegade Tactics doesn't have useful utility -- remember, you're pointing it at Zada, so your creatures can't block, not exactly useful -- but being 1 cmc makes it way better than Accelerate, which has haste but costs double the mana
They could ban Vivi in Standard, in which case everyone who spent a lot of money on Vivi cards (currently going for like 40-55 bucks each as of this writing) would be pissed off, although Id argue that if you bought Vivi knowing what was happening you factored that in as a possibility
Budget also factors in
At some point, card rotation affects just about all trading card games (except for Yu-Gi-oh
Up from a historic low, a period during which you could actually arbitrage copies of this monster, I think Vizier is poised to be a $7 card