A scholar of the Supreme Court and its relationship to the people of the United States says that President Joe Biden’s proposed term limits for justices can restore the court’s eroded legitimacy.
This is one of the exact reforms I've been talking about wanting for years at this point. 18 years is a perfect tenure for someone as influential as a Supreme Court Justice, and giving every president 2 nominations is a good number to keep the values of the Supreme Court in line with those of the public.
also early retirements, stonewalling via the senate as with Merrick Garland… guaranteed gaming the system with those would become much more common. So yeah it’s much much more complicated than just saying one every two years.
Most likely you'd have to allow the sitting president to appoint an acting justice to serve out the remainder of that justice's term. Yeah we'd still have the problem of RBG dying under Trump and giving us a 6-3 conservative majority, but if she only had a few years left on her term when she died the damage would at least be limited.
As for what McConnell did to Garland, having term endings scheduled would make that a lot harder. If their terms are staggered such that they always end 1 year and 3 years into each president's term it destroys the argument that it's too close to an election and the people should get to decide who makes the appointment. They'd be forced to outright deny the nominee and let the president try again. That's much harder to maintain.