got his E heavily altered recently.
They made it a charge system and adjusted the heat buildup accordingly. By and large, a net positive for rumble. Further, Renekton had adjustments to his damage and rage buildup in mid-season 5 I think.
Season 3 was a long, long time ago.
The point was that, until recently, Renekton hasn't been LCS worthy for the most part. Rumble, on the other hand, has been consistent with the exception of that period where it was all Ekko/Shen/Gnar.
Riot doesn't touch Renekton much because they consider him the standard to which they should compare all other top laners.
The "Renekton bar" was complete bullshit and was a poor way to balance top lane. Almost anyone, including Rioters, will tell you it was stupid. If you didn't play Mundo or Shyvana (and maybe like 1 other champion I'm forgetting about) into Renekton, you were throwing the game. To say Renekton is still the bar is narrowminded imo; the current situation is hardly comparable to that level of bullshit. If anyone has been the bar for top lane for the past season, it was probably Ekko. Ekko singlehandedly forced several picks out of the meta when Tankko erupted in pro play. Renekton did the same thing, but that was a long time ago, and I severely doubt he is capable of doing that now.