Good call... Gusy down at Ibanez (or anyone with both a locking and non-
locking nut guitar at home)- try this:
-take the guitar with a locking nut, and play a first position, two finger Fm7 voicing such as this:
|---|
|-1-|
|-1-|
|-1-|
|---|
|-1-|
Play the F with your middle finger, and the Ab triad (other three notes in Fm7) with your ring finger. Doesn't feel so good, does it?
-Do the same thing on a guitar with a conventional (F*nder-style) nut. Smooth as butter.
I know, the pointy-headstock, locking nut thing doesn't appeal to a lot of jazz guys, so this isn't a HUGE deal... but some of us metal types like to swing on occasion too...

A smoother, more rounded (and if possible, lower-profile) locking nut would be HUGE in terms of first-position playability.
-Drew