Which one is more important remains the question, which feature is more valuable is also a matter of question, is it the 21M cap, or the free storage of coins, hard to tell which one to sacrifice when the time comes.
They're equally important. Arbitrarily altering the inflation schedule, and collecting a "storage tax" from every Bitcoin address will have the same effect. De-valuating the currency. Collecting "storage tax" only from "lost coins" doesn't hold water, because besides being incapable of distinguishing lost coins, they are pretty much finite, and once collected, you'll quickly run out of incentives.
A government carrying out different attacks just to damage bitcoin is something different, you could argue that if needs be, it won't matter much how much hashrate is securing the network, if they label mining bitcoin as a crime worldwide, 90% of miners will shutdown and then it will cost them little to nothing to attack it.
What one government does, isn't necessarily in favor of the rest of the governments. Quite the opposite. Whenever some government tries to ban bitcoin mining, there appear mining paradises somewhere else.