Since the filibuster isn't a constitutional issue, I don't understand the argument.
It's been several years ago, now since I read it, so the exact number probably has changed, but at the time, an article pointed out that with the filibuster 11% of the country could veto change.
I keep asking for a unicameral legislature based on population + a direct election of the president. If the people want you to wield power, you wield power. If you screwed up, you'd get tossed. Easy-peasy. Every X years we'd see which politician was "far left" or "far right". Who could ask for anything more?