Looks like more thought was put into eye candy than input dev.
> xset m <ACCELERATION> <THRESHOLD>
and:
> xset r rate <delay in milliseconds before auto repeat starts> <repeat rate per second>
I'm of the opinion that it's not a window manager's job to deal with mouse acceleration or keyboard repeat rates in the first place.
https://bugs.kde.org/show_bug.cgi?id=31189
Anyway, I certainly agree with your opinion. It is just that I think E17 is more than a window manager, and I would place it in the same category as XFCE.