I recently applied a variety of keyframes on a text layer, to shape/simulate a hand that is drawing on the top of it (see screen shots). The problem is that the hand is moving pretty fast and so do the keyframes. It seems really "unreal" and the keyframes flicks a lot.
Is there any way to make the keyframe movement/curve smoother or softer? I have played a little bit with the keyframe assistant but unfortunately without good results.
Good results require hard work. Rotoscoping, especially, requires lots of time and intricate drawing of mask shapes.
By the look of your examples, your masks are very basic straight lines. You should be drawing curves around the actual shape of the hand and fingers, rather than simple straight lines.
You might find it a lott easier to duplicate the arm layer and rotoscope/trace it directly, rather than masking the text layer. Place the masked layer above the text layer when complete.
Start here in the Help files for assistance.
Looks like you're applying the mask to the text layer when you should be duplicating the video layer, using rotoscoping techniques to cut out the hand on the top copy, then placing the text layer between the two.
You should try the RotoBrush for this. It's much easier than doing it by hand.
When you are doing roto work you must separate fields.