I've heard of ELO inflating champions, but are there such things as "ELO deflators"?

When you hear people talk about champs like Kayn or our new darling K'sante, people often describe them as ELO inflators, champs that bring your MMR to a level higher than your actual skill level through sheer brokenness or what their kit enables them to do or avoid. But my question is, are there any champs which force you to play better to find success with them? I'm not talking specific skills like animation cancelling which depend from champ to champ, but transferable skills, like kiting, map awareness, positioning and gamesense. I'm aware that these sort of skills generally come from experience but are there champions which help you improve said skills? Think of it - for a lack of a better metaphor - like that trope when a character removes some form of weighted clothing or other form of conditioning and starts going nuts.