How do you propose delegates to a convention would be chosen?
If it is by election, the same bums as are in the Senate will be there.
They would then throw out all the protections we have in there.
It would be worse after they screwed it up.
It would not even have to have any super-majority of the states as it is now.
And if the set of scoundrels we have in the Senate now won't abide by the best Constitution ever written what makes one think they will obey any revised version of the one we have now would be my question. No need for a Constitutional Convention, just enforce the one we have now.