You're basically talking about giving multiple champions Vaporize and/or Arrow Eater and whatever other effects for just 25/30 nora. Think about it a bit from the perspective of the other player. How would they even deal with it? And it's not like the champions themselves are hard to place down. 68 for Amethyst who you're definitely gonna play anyway (and who is the main problem champ with your suggestion, followed by Amber) and 25-30 for mass Vaporize. And everyone else is cheap too, save for Amber and Obsidian (not counting Platinum because I wouldn't run it in its current state, but I could be wrong about him). Now, granted, you do require positioning and it is only 1 round, but I still doubt this version of the spell would be ok. Powerlevel aside though, I'm not fond of the idea design wise, because it puts them right back where they started. Sure, they don't need to clump up all the time now (and that's a relief), but it's basically the same problem as with the old Sigil, except toned down.