So the scenario becomes: a) use DNS b) use "central"-ENS, but if the domain is already registered now I have to sue some .ch organisation to unregister it. c) use regular ENS and live with whatever namespace entries are free

a) offers everything b offers, but its likely cheaper and has a real-world dispute resolution process.

Take a look at the grandfather of decentralized DNS namespace; .bit from namecoin. After 6 years it has not found its place in the internet name ecosystem.