Hello, Mr. Darius is getting a Loot-Exclusive skin on patch 7.7 and it will be Loot-Exclusive! Your only chances of nabbing this sweet gem ;) of a skin is by gathering all the Chaos Emeralds and defeating Dr. Robotnik, I mean... by gathering 10 Gemstones, which are given to you pretty randomly in the Hextech crafting system. You also have a minuscule chance of him just appearing in any chest.
People are saying this is a problem for various reasons. Why? Because it is.. some people have gotten Hextech Annie and/or Soulstealer Vayne for free and are pleased. Some people have spent hundreds of dollars to obtain these skins and either have too much disposable income or heavy regrets, possibly both.
Now you see, we can work with 10 Gemstones. Gemstones can turn into a Chest and Key. So someone at Riot believes one Gemstone is worth one Chest and Key, which in turn is worth 195 RP. Thus making all of these Loot-Exclusive's just a bit more than Legendary Skins in their eyes. Now, I'm not saying we should be able to buy Dreadnova Darius straight with RP nor am I saying we should be able to buy Gemstones. So where am I going with this? What has Riot wanted to implement into Hextech Crafting but so far has done it poorly? Champion Mastery.
Now based on the above Hextech Annie, Soulstealer Vayne and Dreadnova Darius should appear within about 10 Chests since that's worth about 10 Gemstones, that's fair. That should be about their droprate. They can make it a bit higher, maybe even 1 in 20 and then from there add in Champion Mastery, Let's say every level in Champion Mastery increases the chances to get these skins by X% so that at level 7 Champion Mastery, it would still take you about 10, I'd hope chests to obtain your skin with every failure increasing it until it becomes guaranteed by let's say your 15th chest. It doesn't have to be 10, it doesn't have to be 15.. You just put a guarantee on it eventually and add it to a pre-existing system in-game and you'll get less complaints
People will be happy that they know if they grind any of these champions to level-7 their chances increase to a known price, and yes since there's 3 loot-exclusive champion skins now and there's definitely people with level-7 on all of them that don't own them yet. Let's say once you get Hextech Annie, it resets the base chance back to default for Soulstealer Vayne and Dreadnova Darius..
I know this was a lot to read and maybe not the most articulate way of saying it, but those are my two cents.