No, a key you could bind to i.e. [TAB].

So it would be a physical key?
Right then this raises another issue - gameplay would become overly keyboard orientated; the focus needs to be equal between mouse and keyboard.

You make stuff up for the sake of having to oppose something. And its a waste of time for me to explain someone who does everything to not understand or understand wrong. so thats my last reply on that level:

No it doesnt need to. There is no such rule. Its completely irrelevant.

There are issues on targetting (1) while mouseturning, (2) when enemies are moving fast on your screen and (3) when players stand on the same spot.
To all these issues the proposed functionality would pose an improvement. That is what matters.

There is 1 valid concern: It could be used to target hidden players or players inside forts. A solution to this would be to forbid this kind of targetting when there is no line of sight, which should be very easy to implement.

o/

Did I mention an obligatory rule?
I'm getting into preferences here which is a subjected category at best but it is still valid from the customers perspective.
Are you arguing the point that the focus would shift at all or that it would not be a problem? You're going to have to clarify here.
I'm going to presume the latter - personally it would be a problem and I would not stand alone is stating an affection for parity between mouse and keyboard usage. Of course a solution to this would be to allow for mouse-wheel target scrolling in the options menu but I still believe the system would render targeting far too easy.