Yes that how I see it, it would be no different to today and would in fact be more decentralised than what we currently have with basically only 2 countries doing all the mining!

Surely that's the idea of BTC is that it's trustless!

Currently, I don't have to trust the Chinese or Russian miners who validate my transactions, the software keeps them in check. I'm sure if I were given a choice where my tx was validated I wouldn't have those people/countries do it!   

At the end of the day, I would likely trust a central bank way more than some sketchy operation in the arse end of China, but it doesn't matter with BTC where or who does the mining. So what's the harm in letting only Central banks do the work needed to secure the network?

It would remain opensource and controlled by the people....

I can't see any downsides to what I have suggested!?