Rumble and Sivir have been dominating competitive since the new season started and even back in S4
Isn't that enough of a reason to nerf them, even if they got popular without receiving any buffs before? This isn't about my or your opinion on whether these champions need nerfs, this is about following Riot's standards for nerfing champions. It's seriously unfair to nerf/rework champions, that haven't seen buffs before, right after they become popular in competitive (see Lissandra, Veigar) while letting others enjoy popularity for years without doing anything about it.
Another example: Morgana didn't receive any buffs since S2 or even before > She was picked as a support at the end of S3 and S4 > She got a W, E and R nerf, even her passive could be seen as nerfed.

Morgana's nerfs didnt destroy her like
, she is still op , they are buffing
so i wonder if champions like
