There doesn´t seem to be much change. Isn´t the EU constitution superior to local constitutions even now? And if it isn´t and it becomes after the treaty, what´s the big deal. It´s not as if the EU constitution is much different from the local one´s.
I like the fact you can cross borders without sitting in lines for 10 hours(Polish - Lithuanian border anyone), that you can use the same currency in most of countrys(although not here yet) and that a small country like mine has some economical and overall security from belonging in EU instead of being left alone. Especially with Russia going nuts lately.
I agree with Victor that putting something like that on a referendum isn´t going to produce any results. The EU is confusing, I don´t fully understand it and there are so many members. If every country made a referendum on everything, then there´s bound to be atleast one in which the negative propaganda would make people vote "no" and that would be enough to kill it off.
Also noone is going to loose their national identidy if they don´t want to. Everyone will keep their own language, education system, national symbols, etc. The EU is mainly an economic union. And if you use your countrys economy policy as source for your national identidy, then... you´re weird.
And if the things would indeed turn tits up then every member can always use this
new opportunity in the treaty:
"The treaty introduces an exit clause for members wanting to withdraw from the Union."
I would vote "yes" btw.