As I understand it, that ship has sailed. The filibuster rule can be changed by simple majority vote, but only on the first day of a new session--i.e. every two years. That day has passed.
Tragically, Harry Reid let the opportunity to redress some imbalances slip, and now the country will suffer at least two MORE years of gridlock and inaction.
At the very least, we should require talking filibusters. If a senator opposes a bill or action, let him stand up and show it, and be judged for it. As it stands, 40 senators from our 20 smallest states, representing roughly 10% of the population, could block legislation from even coming to a vote. Or the minority party, working in lockstep, can block anything at all. Without effort, or a price to pay for obstructionism.
Secret holds are even worse. One senator can prevent a bill coming to a vote.
The Senate is already profoundly anti-democratic, with a senator from California (pop. 38,000,000 or 11%) having the same voice as one from Wyoming (pop. 576,000 or .18%.
We desperately needed reform in the Senate rules, Harry Reid needed to get that done, and he didn't. Instead he walked away with a "gentlemen's agreement." As if anyone on the other side of the aisle could be trusted to keep it. IMHO Reid should step down and let someone who can actually do the job take over.