I understand where Riot is coming from with the emotes. I'm sure they seem like a fun little feature to add some laughs and joy to the game, and they are harmless right?
One of the most toxic , rude, and downright mean communities I've ever seen in a video game.. and you honestly think this will have a positive effect on the game? I really have tried to look at this from every angle, and every point of view.. but all I see with these new emotes are more bad manner and more tilted players becoming toxic. I don't know if Riot is just trying to make more money (if these are purchased with RP) or if they just don't ever play ranked, but people already intentionally feed or troll or rage way too much already and this is just adding gasoline to the fire. The mastery emotes are bad enough, but now you're adding a jinx making fun of you and 2 characters crying (which will more often than not be spammed to indicate the enemy player crying, not the player using it)
Maybe this could be a fun thing for professional players in LCS, people who are so skilled at the game that it wouldn't tilt them in the slightest, and it could definitely get some laughs from the audience.. however playing solo queue in bronze silver or gold, it will not be funny or enjoyable, it will make you hate life and probably rage, tilt, or you might not even want to play another game of league and take a break all together. I may get some backlash telling me to stop being so soft, or it's just a game, or whatever cliché insult y'all want to throw at me.. but picture this for a minute.
You are mid against a zed who is clearly smurfing or just better than you, he is fed, spamming his laugh, and spamming these toxic emotes while he completely zones you from CS and stomps you no matter what you do. Now you probably think that a jinx making fun of you, or a crying amumu being spammed won't effect you any differently than a normal mastery emote, however I'm willing to bet that won't be true.
It's like when people say 'gg ez'.. the game is already over, and you can move on with your life, but for some reason it still annoys you and makes you want to report the person saying it. Why?? People say it all the time and it's just a dumb comment that means nothing.. but I believe that it's a psychological thing. You just lost a game that might have been close or you were trying your best to carry or maybe it was a massacre, but even though you know ggez is just a troll toxic statement.. in that moment, it could make you feel like you're trash and you probably won't win your next game either.
On the surface, me writing this and you thinking about the new emotes while you're chillin on the forums with no worries in your mind, this could be looked at as a stupid thing that won't effect you at all.. but if you are in game, in a promo series or just having a bad day of league this could seriously influence rage, trolling, intentional feeding, or maybe even quitting in the middle of the game and not coming back.
tl;dr -- These emotes will just make more players toxic and unenjoyable to play with, and the amount of good they will bring will be way below the amount of bad. Maybe they can be used In LCS because professional players don't tilt so easily , but it simply cannot be allowed in low elo, people will lose their minds.