Short version: I would love to see a fast, single-target mana blocker. Not a cutter or a slower, but a blocker.
I use Hansel & Gretel, and I absolutely love them. It’s be hard to find 5* that’ll help me more than those two already do. I just love mana blocking! Mana slowing & cutting like Telly & Neith is alright, yeah, but the Witch Hunter ability is a blast. More 5* witchers please?
Silencing, Hel, Hansel, & Merlin are the sort I’m looking for, where it becomes a game to see how many tiles you can get into your target before it becomes a benefit to them. If it’s just mana slow like Telly then the victim will still thank you for the mana, just not as much.
And yes, I’ll offer my thanks for Miki, Alfrike, & other 5* heroes that do this already