There's nothing wrong with bending gender (as long as it's not bent in a way that reinforces the existing power asymmetry -- think frat boys in drag, which is akin to bad old minstrelsy, as an example of what to avoid). The problem is that Butler's performance theory doesn't suggest _anything_ more than that (in terms of politics); read literally, her theory in fact may not suggest _even_ gender-bending as a tactic (in _Bodies That Matter_, she discusses & criticizes the mainly voluntarist readings given to her earlier work). Neither abolition nor (to use your preferred term, whatever _you_ mean by it in concrete terms when you apply it to gender & gender oppression) "sublation" is on her theoretical horizon (Butler isn't a "dialectical" thinker if dialectic has to entail "sublation" -- hers is "dialectic at a standstill," as it were).
Is abolition a juridical term? Why equate the word with "fiat"? It took the Civil War -- not "fiats" -- to abolish slavery. It took civil disobedience to abolish Jim Crow. And the struggle continues -- we have yet to abolish racial oppression (and its effect -- the idea of race).
Let's get rid of everything that produces gender oppression (and hence gender), from the gendered division of labor to all other social structures productive of sexism. I'd hope Butler would agree with us that's one of the political goals of the Left. I'd further hope that she'd agree that the necessary -- though not at all sufficient -- condition for the abolition of gender oppression is the abolition of capitalism & replacement of it by a democratic system of production for human needs, not profits.
P.S. For a clarification of differences between Hegel's & Marx's dialectics, see, for instance, Roy Bhaskar, _Plato, Etc._, pp. 115-140. Marx himself wrote:
***** In its mystified form, the dialectic became the fashion in Germany because it seemed to transfigure and glorify what exists. In its rational form it is a scandal and abomination to the bourgeoisie and their doctrinaire spokesmen, because it includes in its understanding of what exists a simultaneous recognition of its negative, _its inevitable destruction_; because it regards every historically developed form as being in a fluid state; in motion, and therefore grasps its _transient_ aspect as well.... (emphasis added) *****
Whether or not Marx was justified in adding "inevitable" (most of us would say no), he was quite emphatic about the _transience_ & _destruction_ of "every historically developed form," whereas Hegel's dialectic preserves "partial truths" of earlier historical stages in sublation (rational reconciliation with the actual).