It's quite clearly an exploit.
Not just that it looks absolutely rubbish for immersion into the game, you can use this BUG from the apparent fix of combo-skipping (which is fixed and you cannot get full damage from this skipping anymore which is a good thing so please don't moderate me as that's an ancient thing
)
This isn't an intentional "Game Mechanic" it's a bug occurs very easily when combining some key presses together, and it's not hard after 5 minutes it becomes reflex...
Funcom should be ashamed that they don't focus on addressing these things.
As for it being "skill" based, whether an exploit is skill based or not doesn't alter the fact it is, in fact, an exploit.
Finally whether you do it or not, don't be ignorant to the fact that the definition of an exploit is exactly that, using an unintentional game bug from any form of mechanic that results in the misuse of said bug and as such breaks EULA and basically results in you being a douche that tries to justify it to try and keep said advantage...
It works well for some classes, I am going to try making my argument within the rules not tell you HOW to do it but why it should be fixed is that currently it makes people teleport from where they were on your screen and they land their combo on you whilst simultaneously moving AWAY from aoe cc or dps etc.
I hope the moderators don't think I'm trying get people to do this, it IS an advantageous thing to use as it makes (especially barbs) nearly impossible to hit especially if said class has a speed boost active... servers can't keep up already anyways but this exacerbates the problem.
The main problem for me is actually that jumping should also remove sprint-bar, and 2*that drain while sprint jumping. As people exploit the bunny hop changing direction already and then you can do that with this exploit.
Fix it.
We're paying customers.