Personally, I hope there is an opposition to the Democrats, but not this opposition.
I think of the current Dems as a respectable right of centre party. It believes in a mixed economy. But it is fairly content not to change the status quo so much. Gradual change. It's the old sort of conservative model.
But there's also a viable left-of-centre view that might make a decent opponent for Clinton. One that uses government money for large-scale projects (like the space exploration of old) and that is willing to lean towards more government in areas like education, infrastructure building etc. One that wants to remove guns and clean up money in politics. Bernie's positions, but with a second amendment change as well. So a view of government that is progressive.
Sometimes one view might seem sensible. And sometimes the other. But there would be a decent choice.
Right now, the choice is between the Dems, the wingnut Republicans and the Trump dictatorship. Which has allowed the Dems to bestride both sides of the middle.