What happens to Vilemaw?
The first time I played this mode years ago, I thought Vilemaw was amazing, and far above Baron in terms of design and visuals. Even now, while it's basically gone ignored, it still stands out. I play Treeline from time to time across various accounts when we have 3 people, because Flex is pointless without an actual team system (not what we have now). That being said, Vilemaw has violent animations and its own move with the web and dust visuals, making it very dynamic and exciting. In contrast, Baron feels very static and uninteresting beyond its spawn.
Considering Vilemaw to have a place on the Rift, would be an idea I'd like to throw out there. Whether it be to replace Baron, to spawn after an Elder Dragon, or to only appear at a random pit if Elder and Baron have both been taken and are on cooldown. It's just too good of an epic monster to waste, arguably the best. Alternatively, updating Baron to have visceral animations is an option.