There are many champs that I hope that they go back and visit (LB, Rengar, Kindred, Malz...who else?), to see what they can improve upon, lets not get too focused on the highlights of some misteps cause there are a few in the shadows, and lets not forget some of the changes that were actually good!
Shen will always be tough to work with due to the nature of his ult, tbh he's not that bad and certainly not the worst. Maokai also come out of the reworks much for the better theres really nothing wrong with him, if JG mao needs help just give him some extra dmg on camps and he's fine.
For Skarner they kno they misstepped as someone already pointed out they are looking for a new passive.
For Zac the only problem seems to be his ult, theres less margin of error and its CC potential is takes a lot of his power budget (though I DO have to ask what got nerfed in exchange since his dmg doesn't matter as a tank)
Im starting to understand that for Zac mains losing the FUN of his old ult seems to be the real sore spot for them, so they need to find the middle ground between the fun of the old ult and some of the utility of the new ult. Its simple Bouncing is fun.
Now Sej, her issue is the major misstep in terms of how they decided she should contribute to a team. Making her a CC bot has turned out to be super unhealthy so they definitely need to revisit her and see what her E can provide to the team outside of hard CC that can enable and encourage the team to follow her into battle. If her E isn't hard CC then she can get her old ult back, but hopfully the new E is something engaging.
But YEAH i really hope that they STOP making or balancing champs for LCS, or making champs that have to be balanced for LCS. Ultimately its won't work in the end b/c either they have to be nerfed/buff for LCS which means they don't get played or they get banned cause no one wants to deal with it.