Senna may be problematic but a there's a question we have to ask ourselves.
Tl;dr: Riot releases champs like Senna so the playerbase(also low elo) would be interested in playing given champ cuz of unique abilities or flashy plays.
Would we be fine with a more "boring" champion? Don't get me wrong, I'm not justifying what Senna or other overloaded champions have in their kits. I just think that the problem is that Riot wants to release champions which can make flashy plays or have insane abilities not just for pro play but also playbase generally(even low elo). I myself am fine playing champions with not too interesting gameplay. Garen, Shen, etc. But I don't think that applies to too many players. Everyone is about that Yasuo or Zed or what ever else. Sure I myself like to play those "extreme" champions every now and then but I just feel like players are not interested in passive gameplay(ex: Bard collecting chimes) but want to do um.. stuff. Like can you ever imagine a champion like Malphite being released in 2019/20? Probably not, too simple for Riot. Even if Riot was fine with releasing simple champions I feel like the players would shit on them. People will always whine about something because there is two sides on a coin. No matter what champ, update, skin whatever we are dealing with, there will always be both supporters and haters. Idk about you guys but I'd be totally fine seeing non-flashy champions played in normal/ranked and also in the pro scene. Really tired of seeing the same picks/bans in LCS. At this point I'd be more interested in seeing a full ap Malphite oneshot the entire bad positioned enemy team composition rather than seeing Kai'Sa fly around like super(wo)man or Lee Sin dashing around like as if he were in a bouncy castle..
Passive would be stronger if it just enhanced her next auto and lost the ring gimmick, the extra range, the energy refund, and MS. If it just added a
style effect of extra damage next auto its a stronger ability because she can chain it rapidly with less effort or thought.
Q. Is a long range poke that Has a Slow, MS, HP reign. With out the fact that its cast is delayed by range this would be a excessively strong ability and her E is an AOE high damage Silence into Root.
Q is a long range hook. All it does is single target damage and displacement CC. His E is an empowered auto with knock-up.