Primitive Screwhead said:
As such a Ghost-Touch weapon basically ignores the effects of the Blink spell.
Ghost Touch has absolutely no benefit related to the Blink spell.
When you're blinking, you may be incorporeal, but you are also
on another plane, and the Ghost Touch property cannot reach the Ethereal Plane from the Material Plane.
From the SRD:
While on the Ethereal Plane, a creature is called ethereal. Unlike incorporeal creatures, ethereal creatures are not present on the Material Plane.
and
Since you spend about half your time on the Ethereal Plane, you can see and even attack ethereal creatures. You interact with ethereal creatures roughly the same way you interact with material ones.
An ethereal creature is invisible, incorporeal, and capable of moving in any direction, even up or down. As an incorporeal creature, you can move through solid objects, including living creatures.
It's like if there's an incorporeal goblin on the other side of a stone wall. Your Ghost Touch longsword may be able to strike incorporeal creatures, and the goblin is an incorporeal creature, but your longsword has no special ability to hit a creature who's behind six feet of solid rock.
Ghost Touch is great for striking shadows and spectres. It can hit a ghost who is manifested (and thus incorporeal on the Material Plane), but not a ghost who isn't manifested (and thus residing solely on the Ethereal Plane). It has no special ability to strike someone who is blinking (and thus spending some of the time on the Ethereal Plane), since the times that they are incorporeal, they are not on the Material Plane anyway.
Likewise, as you say, it grant no special ability to reach the Material Plane from the Ethereal Plane.
Note that an incorporeal creature on the Material Plane (a manifesting ghost, say) can use a Ghost Touch weapon to effectively strike corporeal creatures; the weapon is treated as either incorporeal or corporeal, whichever is most beneficial.
A ghost touch weapon deals damage normally against incorporeal creatures, regardless of its bonus. (An incorporeal creature’s 50% chance to avoid damage does not apply to attacks with ghost touch weapons.) The weapon can be picked up and moved by an incorporeal creature at any time. A manifesting ghost can wield the weapon against corporeal foes. Essentially, a ghost touch weapon counts as either corporeal or incorporeal at any given time, whichever is more beneficial to the wielder.
-Hyp.