I don't want the Democrats to expand SCOTUS. I don't like messing with it politically. But Congress has the authority to set its size, and has messed with the size for political reasons before. Of course bad precedents are bad precedents and should be seen as such.
Still, if the Democrats do it, and kill the filibuster to make it happen, Republican Mitch McConnell will be as responsible as anyone. As he always does, he'll pretend he's entirely innocent of having ever played politics, but in the end, I think congressional scholars will pinpoint him as the man who destroyed the Senate.
The weirdest thing is how many progressives want it to be destroyed. It's as though they can't count to 100 by 2s and see why they want the protection of the filibuster. Or perhaps they hope to pack the court so thoroughly that it won't matter for a generation.