Well, the reason to USE tweens is to have it 'more realistic'. If you don't actually draw it all out, it would be better to tween. Of course, propperly using shape tween also helps...
Now, as for not using motion tween... I would hate to see the end result, unless you seriously go frame by frame with perfect positioning, it does get jumpy.
Just out of curiosity... have you done any games?
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I believe society is flawed; our notions on life, on child rearing, stem too far back to be of relevance in this day and time.