Why doesn't HA ever get any of the featured game modes?

I still play URF and All For One every time they come around, but the best time I ever had in league was the day when All For One was a glitch people were messing with in custom games. Everyone jumped to Howling Abyss, not SR, because HA is the natural place to go if you want a game that's messy and chaotic. We're even playing an all random URF mode right now. Why not stick any of these on the smallest, weirdest, best-suited-for-a-casual-match map?