An Idea To Nerf Trist Without Touching Her Damage
I believe changing her Rocket Jump to a charging-channel (like Fiddlesticks) during the wind-up animation would be extremely efficient without destroying her.
One of the single most frustrating things about playing against her is when you CC her and she still hops away as if you never did anything just because she started her animation a fraction of a second before you landed the CC. This change will make it so she has to play smarter instead of having a "Get-Out-Of-CC-Free" card.