(Equipment, Auras you control, and counters are modifications.) The value of X needs to be determined both when the ability triggers (so you can choose a target) and again when the ability resolves (to check if that target is still legal)
As of now, the developers have not commented on Misty, so no change should be expected any time soon
Creatures (26) 2 Verdurous Gearhulk 4 Winding Constrictor 4 Rishkar, Peema Renegade 4 Walking Ballista 2 The Scarab God 2 Herald of Secret Streams 4 Merfolk Branchwalker 4 Vineshaper Mystic Lands (22) Spells (12) Now, we probably dont actually want Vineshaper Mystic, as its probably just too much worse than Rishkar, Peema Renegade while asking a lot more of us
Akela Forest Runner is a very interesting character
(Transfer its materials to this card.) This card is unaffected by your opponent's activated effects while it has 5 or more materials
Its a really potent combination of effects, and thats especially good if youre in a position to take advantage of both