I hate the "If we lose the next presidential election people will realize how bad the Republicans are and we can elect communists!" mindset. That shit never works. After Reagan and Bush we got Clinton, one of the most decidedly centrist presidents in a long time. Bush II basically resulted in this - we got Obama who's the most liberal president America could reasonably be expected to elect in this era. But the ones who bring this up are the ones who bitch about Obama being a secret Republican.
The *only* advantage might be less brutal midterms, but who the hell cares? In fifty years no history book is going to talk about what Republicans in Congress did, they're going to talk about the Obama presidency and the Clinton (or Walker or Bush) presidency, for better or worse and the parties will own those legacies.
So sacrifice congress for the presidency? or sacrifice the presidency for congress?
Which one do you think in the long term will be able to implement progressive ideas?
Both arguably are hard to swallow with today's toxic political environment.