I don't think so. People have been complaining about Congress' dysfunction for decades, even when it was fully in the hands of one or the other party. I don't think Congress' dysfunction has anything to do with partisanship. And yes, "populists" get to have a voice -- that's what it means to have a representative democracy and republic. If "populists" (or whatever) need to be negotiated with, so be it, but it's not intransigence that makes Congress dysfunctional. I suspect the problem here is that you want activist agencies to ratchet-like interpret power delegations ever more broadly as long as you agree with those interpretations, but that is a very risky game.