a charge bar could help you see how long you've been charing the jump, but I think it's better off without. Let's you get the feel of it rather than "alright, once it hits halfway I'll let go and go this far"
in the end charging low and charging high isn't such a difference
charge bar is shared in two parts (1/3 - 2/3) they're for unfinished - ready ... because you can jump immediatly, this bar would have to be changed
becaue you jump automatically after fully charged, there's no need of such a bar
this bar would just disturb ... as Hibiki said ... "would be a total waste"