Probably one of the most convenient QoL features in Apollo was using Haptic Touch (ie long-pressing) to get a quick peek at the parent comment. It also gave you the option to jump back to the parent comment as a quick way to sip around through a post.
It was a super-near QoL addition that made Apollo really nice to use, and I’d love to see it on Memmy as well!
Good point about the memory of certain features fading. I hadn’t considered that.