You do realize, don't you, that a convention isn't limited to a few narrow, predetermined issues? Article V of the Constitution provides that "on the application of the legislatures of two thirds of the several states, [Congress] shall call a convention for proposing amendments, ...." Suppose that conservative/republican legislatures in 34 states applied for such a convention, and that Congress then called such a convention. Presumably every state would then be entitled to send delegates to this convention, although it's not clear whether participation in such a convention is limited to state delegations only (I would guess that this would be a matter of the rules the convention managers would draw up for running the convention). At that point, all hell breaks loose and every proposal under the Sun will be run up the flag, including many that would give pause to a lot of the conservatives/republicans who originally applied for the convention. The end result could very well look nothing like what was envisioned by the legislatures that applied for the convention in the first place. Do we, do you, really want to take a risk like that? I don't.
The last time that a Constitutional Convention was called, it was called to "fix" a governing document that wasn't working as intended.
The end result was an entirely new governing document.
To add to your post, this notion that the document generated by this convention would be more in concert with conservative principles is political pollyannaism.
If anything, it would make the new standard of Constitutional government more liberal, since it would create a document to address the present state of our Union.
Our system of checks and balances no longer functions. The three branches of government act in concert in order to impose a "government for the people" style of governance rather than a government
of the people as intended. There are no better examples of that than the logical contortions used by the SCOTUS to arrive at the constitutionality of the ACA's individual mandate, or the passivity of Congress in the face of Obama's constant encroachments of congressional powers.
The concept of federalism is all but non-existent. States are so beholden to Federal money, and so wary of punitive action by the Federal government, that they are largely ineffective in opposing mandates from DC. There are the occasional pockets of defiance, but very few instance of effective broad-based disobedience.
There is a fourth unelected and largely unaccountable branch of government. Here's Daniel Greenfield on the subject (from
Rise of the Mediacracy)
A nation where governments are elected by the people is most vulnerable at the interface between the politicians and the people. The interface is where the people learn what the politicians stand for and where the politicians learn what the people want. The bigger a country gets, the harder it is to pick up on that consensus by stopping by a coffee shop or an auto repair store. That's where the Mediacracy steps in to control the consensus.
The media is no longer informative, it is conformative. It is not interested in broadcasting events unless it can also script them. It does not want to know what you think, it wants to tell you what to think. The consensus is the voice of the people and the Mediacrats are cutting its throat, dumping its body in a back alley and turning democracy into their own puppet show.
Media bias was over decades ago. The media isn't biased anymore, it's a player, its goal is turn its Fourth Estate into a fourth branch of government, the one that squats below the three branches and blocks their access to the people and blocks the people's access to them. Under the Mediacracy there will still be elections, they will even be mostly free, they just won't matter so long as its upper ranks determine the dialogue on both sides of the media wall.
Government by Executive fiat is the norm, and not the exception. Beyond that, Barack Obama's mere utterances modify standing law, making the White House Press Room a third and omnipotent branch of our alleged bicameral Congress.
We need a new Declaration of Independence, a listing of our grievances, before we think about a new (or revised) Constitution.
It may very well be "course of human events" time again.