This is clearly not the game I was playing. It has to be admitted that enemies are slower than you but that's due to the fact that you are the motherfucking witcher - a superhuman expert swordsman, whereas they are merely humans that have to make effort to swing a
Zweihänder or simply are not that good at swordplay at all (they are mere soldiers and ruffians, as opposed to an elite force). I found that remarkably consistent. I have not seen any significant AI issues, least of all issues you write about.
I think you should listen to
Comrade Goby's advice and stop living in a dreamworld, where they make excelently balanced games with the exact gameplay you require.