I was referring to the bind and the shield, that's 2 similar abilities.
Rest of him is totally different but just from playing morgana you can get used to HALF his kit, which considering the rest of his kit is a passive with a bush and a basically tibbers it's not that hard to get if you've played morgana.
Reason I mentioned her is her bind and his root are super similar and his root is the only thing in his kit that's a skillshot, rest of it is decision making, which you won't get that much better at playing ivern more really.
I know I repeat myself a lot but I'm just trying to say that characters in league for the most part aren't that difficult to do decent with if you understand how to play with similar abilities.
I can give an example actually, granted I'm in potato elo and your mileage may vary but people I play with are at my skill level, when I first played thresh after I started to understand the game some more on a free week, I did pretty well with him. I wasn't godlike amazing omg wtf (remember I'm not great at the video game) but I could understand him and play him at a level that worked with my skill level because I understood how his abilities worked through seeing him on videos and through playing similar champions with similar hook like abilities.
I'm saying (repeatedly I know, and I apologize that I'm so long winded and rambly but that's how I am) that drawing upon past experiences is how we succeed and banning something you know your friend wants to play because you don't trust them to try their very best and do well is just ridiculously rude.
I once again would like to say I don't condone the kat pick and find that both the OP and the person in question to both be acting like hmm, like instead of teammates they're arguing like siblings. You know where one sibling takes something away so in return the other sibling does something else to be annoying and it just cycles from there? That's not a good way to act with people ya know?