Irelia Nerfs Suggested By An Irelia Player
It probably goes without saying that Irelia is overloaded to some degree, being able to do too much all at once. While I find Irelia a ton of fun to play and having some degree of counterplay in that if she misses her marks she's basically useless (unless she's already 10-0 with 200+ CS at 20 minutes) there's no denying she has too much going on. With that being said I think I know how to nerf her in a meaningful way, reduce her move speed by 10, that'll do it.
Joking aside, I think I actually have some decent ideas on how to nerf her being an Irelia player.
First off, Defiant Dance should not make her CC immune. It should be able to channel through CC similar to Garen's Judgement (E), but she should not be able to channel it for a fraction of a second just to avoid being stunned or rooted and then dash in and kill you after you wasted your peel. Being a mobile champion CCing her should be one of the main ways you prevent her from getting onto carries and killing them, but if she can just toggle this to block your CC in the middle of jumping around at 200 MPH in order to dodge skill shots faster than Yasuo she is way too hard to lock down. This will also make her a bit easier to catch when trying to kill her, but I don't think it will effect that nearly as much.
Secondly, reduce the range of Flawless Duet, in the sense that she can't cast it as far away from herself. Flawless Duet allows Irelia to poke quite easily despite being a melee champion, as well as apply pressure for several seconds in lane after placing the first one threatening to stun and trade if you don't back off. If Irelia is going to be as mobile as she is she shouldn't also have a strong presence from a distance and be able to set up to do tons of damage without putting herself in any real danger. Reducing the range of Flawless Duet will mean she needs to get closer to make a strong trade in lane as well as get closer to the enemy team if she wants to land multiple marks and start jumping around to get into the back line and do serious damage while resetting her dash every time she marks or kills somebody.
Finally, remove the bonus damage to minions on Bladesurge. I was playing her before this was added and I can't understand why it's needed, Bladesurge already does more damage than her basic attacks and is an extremely fast dash so there should be no issue last hitting minions, but there's more to this buff than that. With the bonus damage to minions not only is it easy for Irelia to clear wave very early on, but she can also use minons as somewhere to dash to without putting Bladesurge on cooldown much more frequently. This has multiple benefits, she can use minions to escape a gank, dodge skill shots, wait out cooldowns at a safe distance, or dash in after placing the first blade of Flawless Duet in order to set up for a trade or all-in when moments earlier she was at a safe distance for the enemy laner to farm. Reverting this is a simple nerf, but it will actually nerf her laning phase a fair amount.
I haven't been specifically looking at things people hate Irelia for aside from the general notion that she does too much, but I think these are some good places to start at least. If there are other things everybody hates and want nerfed I'd be interested in seeing what people hate Irelia for.