There is no goal for testnet to be POW or permissionless or without a central authority. It just exists to help the developers of the software test it. It is not a currency, it is a testing fixture for the developers of the software. Any time it turns out to be less good for the testing its developers intend for it, it'll get discarded and replaced with an updated test fixture. This is no different than throwing out calipers with chipped jaws or a shop rag that is too oil stained. To the extent that testnet might have some relation to those things (like having POW) at all is simply a product of the fact that it exists to test the Bitcoin code.
My testing should be none of your business. Do you think private companies need approval from you or anyone else to do private testing?
The goal of Testnet is to mimic Bitcoin as much as possible without appearing to have a long term store of value and potentially compete with Bitcoin. Right or right(ish)?
Regardless of the goal, POW mimics Bitcoin... (changing that hurts, as displayed in real life at this moment). And having a central authority could cause unexpected issues.. Of all types. I think Bitcoin is beautiful because it doesn't do that, no one should download a Bitcoin client and get something centralized IMO.
If your cool with that, why didn't you do it when you had Bitcoin commit access 2012-2015?