Win with 8 different legends was bad challenge.
I have 7 wins with 7 different legends and absolutely 0 idea who all 7 are. I'm hoping I don't have one on Horizon and playing her. I'm going to be a little annoyed if I grind 20-30 matches finally get the win and find out I already have one with her.
From there this is like the location specific challenges from season 3. I would not mind it, IF it were win with 6 different legends, but 8?! I think many players are going to struggle to complete this challenge even if they are slightly above average in skill. Even if it was get a win with 6 different legends, many players will struggle.
Many will be lucky to have a win ratio of 5% with a legend they main and are good with. Just at those rates they would have to play over 200 matches. When you force them to attempt this with 8 different legends it ultimately means playing legends they will be horrible with. That means a lower win ratio and hundreds of matches played chasing this challenge. Those matches are not only not fun, but extremely frustrating because you're being forced to play legends you don't like and are not good with.
I'm all for challenges being challenging.. Pursuit of badges like the Triple Triple or 4k is challenging yes, but it's not frustrating.