As soon as we get some workflow polish, this can be a great After Effects competitor (there is no decent one in the market atm, btw). I've been animating in AE for 10 years and the best thing it has is fluidity of use in the UI. If you ever need it, I'd love to test dev builds, do live testing and give feedback along the way.
I could get very particular about this if you guys would find it useful, but I'll leave these simple but ESSENTIAL points; I believe no animator would take a keyframe-based program seriously without them:
-The MOST important thing is you should be able to drag the cursor to make a selection area, this is vital for keyframe management.
-Dragging a keyframe should select it and move with the cursor. Right now it makes a duplicate when you drop it with values that have no apparent correlation, and undoing does not erase them.
-Shortcuts for adding properties when an object is selected (pressing A adds Angle property, T for Transparency as it's closer to the left hand than O for Opacity, S for both Scales [X and Y], W/H for Width and Height...)
-Autokeyframing (toggleable) ON by default (when you drag an object and are in a moment in time that has no position data, add new keyframes and position data automatically. Same applies for angle and size)
-Buttons for going to the first/last frame, keyframe skipping only is not enough.
-"." and "," or left/right arrow keys should move frame by frame.
-Ctrl+D for duplicating any currently selected keyframes one frame forward, overwriting the former if there is any. Essential for timing and pre-posing.
Complex to implement but ESSENTIAL on the long run:
-Scrubbing the cursor should update the view dynamically so you can instantly see how it's looking. If this is implemented, clicking on a keyframe should not bring the time cursor to that point, it should only select that keyframe and update the properties panel.
-Double clicking on a keyframe should bring up a easing editor, same as editing it on the layout directly but on a linear timeline with precise scales/rules (see After Effect's implementation). I can't express how important this is for any animator.