Steve -- I wrote Xporter specifically because I didn't think Exporter had done the right thing.
Secondly, I can hardly see the worry for confusion, since the control of using Exporter or Xporter is up to the library-module writer -- and they can choose what interface to offer to the user -- Since how to use optional arguments in "use module(optional args), is always module specific, any exceptions to normal usage would be documented.
Should I be confused when (:xxyz) doesn't work on some module? i.e.
what you put after "use mod" is highly module dependent.
Third minor nit, it's trivial enough to eliminate the defaults
use mod([!|-] <other options>); Using ! or - by themselves negates the default (as one might expect).
Neither of those issues covers the fact that with Exporter, you must explicitly include it in your @ISA for it to work (or import it's methods). Why put such a bother on all users when it's the normal case? -- I.e. In a non-OO module, why shouldn't adding to the @ISA of the calling module be the normal case? It certainly seems to be a more user-friendly design -- which has been the point of all of my modules.
Just because someone else did a non-userfriendly design 1st doesn't mean it should not or cannot be done, IMO, more user friendly.