Syria's announcement a couple of days ago that it would hold a referendum on a new constitution does not seem to have convinced many people that any real change is afoot; after all the following day the best-known dissident blogger, Razan al-Ghazzawi, was arrested again, and no one can comprehend how you hold a referendum on two weeks' notice in the midst of a near civil war.
The past year has seen plenty of examples of dictators promising reforms that are too little, too late, and merely symbolic. Daniel Serwer labeled the attempt "bizarre."
I should note, however, that there was some substantive discussion of the proposed constitution over at Syria Comment a couple of days ago, and you can read the full text (in Arabic) of the proposed new constitution here, if you're so inclined. None of which changes the likelihood that this particular proposal is pretty much dead on arrival.