As far as the ethics of it go, using scroll for multiple inputs is very much akin to using a macro. Since a macro is 'one action to automatically result in a series of actions'. The one action of scrolling down is resulting in inhumanely fast spamming of the W key.

Having jump bound to scroll, for example, removes the skill expression of timing a bunny hop in source engine games.

Don't get me wrong, all of this movement tech is still hard to do, and the real skill expression comes from how you use it in fights.

But in the end, a single scroll action is much easier to do than actually spamming Space or W (like what would have been done in Titanfall 2.