Not sure if there is a proper place to propose/vote on suggestions. If not then I suggest set one up.
Just purchased 2dtk yesterday, here are some of my initial suggestions:
1:
Improve "Autofill": It only seems to work if filenames end with the whole number; 1, 2, 3 .. 10, 11 .. 100, 101 .. etc
However the first time I used this I had something like 'frame001player', 'frame002player', which didn't work.
Also even if the filename has a few 00s before the number, 'frame0001', 'frame0002', this also prevents autofill from working.
I suggest that autofill grabs the order they are as in the sprite collection. At least that way, even if the order is wrong, or the wrong frames are inserted, it is easier to delete than to manually add each frame.
2: When closing the Sprite, SpriteAnimation, etc. window, if changes were not committed, then prompt for confirmation before any work is lost.
The 'commit' button isn't a normal Unity workflow so I'm sure it catches a lot of people out.
Otherwise, I am enjoying 2dtk so far.