So unless I'm missing something.
Earlier this year, Riot rotates through game modes for a few months (ascention, ARURF, Poro King, etc.). Then they stop for a month for... some reason. They then fail miserably at Clash. Rotating game modes stop altogether months. Now nexus blitz is a thing that has been here for a whole week.
It's hard to imagine that this is what rotating is supposed to mean.