Consider that you have an internal wiki link that doesn't use a pipe, for example "[[Danzig]]". If you edit the page in VE and change the text from "Danzig" to "Gdańsk" without using the link inspector the result will be "[[Danzig|Gdańsk]]". See the history of https://en.wikipedia.org/wiki/User:Amire80/links-nopipe .
It is not obvious to the user what is happening - does the target or does it not? The users may want to achieve one result or the other in different cases. My own hunch is that users will more frequently want to change the target as well, although that is just a guess.
If we have a reason to think that one behavior is far more common than the other, then it should be the default. If we are not sure, than some more indication about the target will be useful. The only ways to be sure before saving are to check the diff to open the link inspector.
Version: unspecified
Severity: normal
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=54947