@Riot In light of Leblanc's upcoming partial revert...

What about Karma? Considering her gameplay/balance issues are the result of her 5.10 changes, and the subsequent efforts to make them work - wouldn't this approach be equally as applicable to Karma?

Perhaps that way you'll have a better base for whatever mechanics you change in her 2018 update.

Edit: Meddler: Leblanc has some issues that we definitely want to address at some point. In her update last year, we resolved some of the problems that plagued her but introduced some new ones in the process. We took some time recently to test several variations of new spells on her kit. While a lot of them were interesting, they didn’t feel like the set of changes that would solve her problems and satisfy the desires of both camps of Leblanc players (those that prefer the old version and those that prefer the new one). If we’re updating Leblanc again, we need to make sure that it nails it, rather than just creating an additional group of players that prefer now an additional version of Leblanc. Having not found anything that we were satisfied with yet, we’re opting to table further Leblanc rework explorations for now as we focus our efforts on systems and champs that need more urgent attention (ie. Runes Reforged follow-up). For the time being, we’re going to look to tweak some things around to be a mix of both pre- and post-rework Leblanc until we have the time to invest deeply in kit explorations again..

^ That is literally what Karma's rework did, then again with her 5.10 update.