So, currently UMG enables animation through the proto-sequencer, which works fairly well, with one very clear exception: the keyframe interpolation only currently supports linear interpolation, which is pretty limited. While it is certainly possible to fake most other interpolation curves with enough keys, it’s a pretty ugly, tedious process.
Lacking the option of Timeline components for widgets makes it even harder to fully hand off to artists.
At the very least (assuming curve assets aren’t possible), I’d like to see Discrete interpolation, Cubic, or possibly the ability to specify an easing function/direction. Ideally, we could select a single keyframe for a single property and directly set the interpolation type, or curve asset. This is a priority for our UI artists, and currently their largest gripe about the system.