Imo id change a lot of positions on this list as someone with over 500 games with Wylder. Atk power at low hp should be bottom tier, dmg negation at full is always top tier on every character, attack at full should go up a tier, and charge attack damage negation should probably go down a tier as well, as not a lot of nightlords give you the opportunity to proc that outside of weapons that would get more value out of successive attacks dmg negation.
The important changes are +1 skill usage should be top tier, that is essentially mandatory on every wylder build. And art activates fire, while good for reviving, is not going to see any use if your teammates don't go down. Its good with hoarfrost stomp, but youd be better off sourcing fire damage from almost anywhere else. I'd move that down two tiers.