It's very frustrating when you have a lot of animation keyframes in an On Scroll animation for example and you just want the whole animation to start a little earlier or later. Currently trying to move multiple keyframes up or down the timeline just combines them all together wiping out the whole timing. The closer it functions to the expected animation timeline UI the better
I'd say this whole section could benefit hugely from a redesign. You can't zoom the timeline so there's very little room to play. I get why it's a vertical layout but more room here and grouping features would be great.
Also it's very tricky to adjust timings of the feel of a website as it scrolls. So allowing you to group and set say the amount of percentage that group takes up would really help. Imagine the groups took up vertical space and could be clicked into to reveal their animations within their allocated space.