Good luck convincing the rest of the country to give your region 10 new senators.
I don't think we've ever valued democracy for its own sake. The founders were much more focused on the States and checks and balances. Democracy had to fit into that framework.
[Edit] the proper rights of a British subject became the proper rights of an American citizen and should affect the House directly.
First, quite obviously, the borders of California were no part of that deliberation.
Second, the focuses of the founders don't have to be our own. They had legitimate concerns, of which we should also not lose sight, but that doesn't mean democracy is an illegitimate concern.
As to unreasonable: It's a rare issue that unites the smaller states. From a national political perspective, Vermont and Wyoming couldn't be much further apart. So I am not persuaded by arguments that assume there is a threat of a small-state Senate alliance against the overwhelming wishes of the rest of the country.
On the other hand, if you want to argue that overuse of the filibuster has put an inordinate amount of legislative power in the hands of the Senate majority leader and a dozen middle-of-the-road Senators, I agree. But the solution to that problem is to fix the filibuster, not destroy the Constitutional balance between states and the Federal government.
"From a national political perspective, Vermont and Wyoming couldn't be much further apart."
Vermont and Wyoming are strongly united on a number of issues (guns immediately springs to mind). I'm not the least bit sure that Central California and Silicon Valley would be united on fewer. The notion that Vermont and New Hampshire should be separate; Connecticut, Massachusetts, and Rhodes Island should be separate; Maryland and Virginia should be separate; but Sacramento, San Diego, Los Angeles, and San Francisco all belong in the same state is laughable.
"But the solution to that problem is to fix the filibuster, not destroy the Constitutional balance between states and the Federal government."
Right, because when they wrote the Constitution, Jefferson and Madison and friends carefully laid out California's borders.
When California entered the Union, its population was less than 1% of the total US population. Now it's well more than 10%. The borders that made sense when it was a state like Wyoming don't make sense anymore. It has population like the eastern seaboard, it has industry like the eastern seaboard, it should have borders more like the eastern seaboard.