Not only an Art V would be hijacked by a Soros or similar other statists...you will be asking politicians to implement Art V who cannot even follow the Constitution
I am totally for an Article V convention as you can see from my tag line. BUT, you hit the nail on the head for one good reason to not have a convention. The DC tribe will just ignore any new amendments made as well as the rest of the constitution.
On the other hand, a convention will force the statists on the defensive where they would once again overplay their hand.