I think people are overexaggerating bass here. The GX has absolutely fantastic bass extension and presence. It's just tighter and more refined. Less bloomy and warm. It extends all the way down, and if you have bassy music, the bass is all right there. Unless you like an obvious emphasis on bass, I don't see how the GX bass is 'lacking'. Hell, I have a Grado White headphone on hand, you wanna talk about lacking in sub bass, that'll really show you just how much better the GX is at representing sub bass.
Yes, it ain't an LCD2 which is bass and mid first then treble. This is more of a balance between bass mids AND treble. That's the nature of the upper range being less dipped down on the GX, so there is less 'focus' on bass and midrange, and more of an even approach.
You can't have an LCD2 tuned to have better highs with the same exact bass and midrange. There is always going to be a change in audible presence when you skew things differently.
There's no such thing as forward bass, forward mids, and forward treble. You can only pick two, or have a linear balance between the three.