Knightfall - There's a trick ... Auto!

Yeah, this is the kind of bad event that makes ppl hate CG. 

If, for game balance purposes, you shouldn't be able to beat it with a maxed out 5-star toon (every gear and ability increase available at 5), then don't offer it to 5-star toon owners. Telling ppl to spend hours of their lives playing an event that is more frustrating than fun is just bad game design. 

Deny players the shards the easy way: just don't allow them to be eligible for the event until their toons can beat it. No one would care that they aren't getting t2 or t3 rewards if there was a clear eligibility requirement that they didn't meet, bc they would know that the event is fair and that no one else with a comparable toon got those shards either. it's fair. 

Right now, insanely lucky players will get more shards -- sometimes dramatically more -- than other players without actually investing more or playing smarter. Some players will feel frustrated by the unfairness and quit trying, and some players will play the event over and over -- they'll get the shards, but they'll resent the game designers. It's a bad idea. It's bad design.