The treaties subsequently signed-off by PM's leaves more than a lot to be desired, notably that of Lisbon.
Whilst I can see that you might quite reasonably consider powers enacted by executives rather than legislatures sub-optimal, how will this improve with Brexit which will just be a power grab from the Executive over items that previously had European checks and balances in place through the democratically elected European Parliament?
We're already seeing that the government's plans (if we can be generous enough to describe them as that) involve giving power to ministers and not Parliament.