The nub of the unorthodoxy can be found in that phrase "as now practiced." In other words, I am saying that a change from using the filibuster rule from how it has been used traditionally --only in somewhat extraordinary circumstances-- and how it has been used by today's Republican Party --as an across the board hurdle for passage of any legislation-- alters the status of the rule and its relationship to the Constitution's expectations regarding the Senate.
Thus I argue:
The filibuster has become unconstitutional. The filibuster is not even a law. It is just a rule of the Senate. It is below a law, and the Constitution is a level above the law: the ultimate authority.
The inferior was allowed to dominate the superior. What could be acceptable used in a minority of instances becomes a violation of the spirit and intent of the Constitution if is exercised all the time.