Two, there should be a limit on the amount of filibusters within a year, session, or whatever period makes sense. Kind of like coaches challenges in NFL footb
This would effectively eliminate the filibuster in one-party rule situations like we have now or had early in Obama's first term. What the Majority Leader will do is fast track a bunch of "must filibuster" legislation that was never a real priority for him early on just to make the opposition party blow all its filibusters. Once they had done that, then he'd move on to the stuff he really cares about.
Eventually, either they reform this thing responsibly or one party is gonna get rid of it altogether. When Dems reclaim the Senate, they'll have no interest in mercy.
They won't have any mercy, not that they were having much mercy before. Both sides can tinker with the rules all they want, but the real root of the problem is that the parties and much of the electorate is overly polarized, which has led to a polarized Senate. Very few moderates gets elected. Back in the '90s or even the 2000s, if the Republican leadership got particularly aggressive, they'd lose people like Lincoln Chaffee (Rhode Island) (and previously his dad, John) and Jim Jeffords (Vermont) and less frequently, Olympia Snowe (Maine). On some issues, they'd also lose Bill Roth (Delaware), Arlen Specter (Pennsylvania), Alfose D'Amato (New York), Bob Packwood (Oregon), Mark Hatfield (Oregon), or Slade Gorton (Washington). Not everybody was Jesse Helms (North Carolina).
If Democrats got overly aggressive in general, they'd lose people Fritz Hollings (South Carolina), David Boren (Oklahoma), and James Exon (Nebraska). Those guys were more conservative than probably half the GOP, and they'd ditch the leadership on anything. If they got too socially liberal, they'd lose Robert Byrd (West Virginia), David Pryor (Arkansas), Dale Bumpers (Arkansas), Bennett Johnston (Louisiana), Harry Reid (Nevada) (he used to be pro-life - hard to imagine now), Tom Daschle (South Dakota), and Howell Heflin (Alabama). If they got too fiscally liberal, they'd lose Kent Conrad (North Dakota), John Breaux (Louisiana), Jay Rockefeller (West Virginia), Dennis DeConcini (Arizona), Richard Bryan (Nevada), Joe Lieberman (Connecticut), and Ben Nighthorse Campbell (Colorado). Believe it or not, they occasionally even lost Dianne Feinstein (California) if they got too fiscally liberal. Not everybody was Ted Kennedy (Massachusetts).
These people made it harder to unreasonably invoke cloture and (on the flip side) maintain a filibuster. Nowadays, most politicians who did what these folks used to do would get demonized as "soft" and face primary opposition. There are still a few but no where near enough to make a closely divided Senate work.