If the Republicans agree to impeach, they will be setting their own party on fire.
That may be exactly what the country needs to move forward to a politically more functional future. The Democratic Party is in the midst of an identity crisis and the Republican Party is not much different in that regard. The two-party system's flaws were laid bare in the 2016 campaign. Sanders and Clinton represented fundamentally different groups, as did Trump and the establishment Republicans he defeated.
I don't believe two parties provide the flexibility modern-day America needs to breathe. The only reason they survive is the ballot access laws that make it very difficult to run for office as an independent or other-party candidate. Busting apart that artificial structure will give people room to align their political beliefs and deeds. I'd prefer to see multiple parties cooperate to govern instead of two parties working to defeat each other. It's not really two parties anyway, as the Trump/establishment and Hillary/Sanders splits show.