"...the community could decide to destroy ninja-mined stake."
All Steem originated via the ninjamine. Steem disbursed as rewards since then was not mined, but all other Steem was mined. How do you propose that stake originally not produced via the rewards mechanisms be separated from Steem created through the rewards pool?
It is not possible to burn or otherwise destroy ninjamined stake as a whole. There simply would no longer be a nominal supply of Steem without mined tokens.
Just cut to the chase: the founders gained too much stake to enable the blockchain to remain decentralized if their representations that it would not be applied to governance have been renounced. It is that specific hodling that threatens governance, not all the rest of the Steem in existence. The reason it is a threat is not because it was mined, but because it is so large the governance mechanism cannot survive it's application to governance.
I agree totally and don't have a specific proposal for addressed mined STEEM, except that we probably shouldn't encumber or interfere with it until there's a hard fork resulting in two chains going forward.
If an entity like Tron or the exchanges decides to hardfork and therefore create two chains, I think it's more justifiable to punish them and their tokens on the legacy chain.
Freezing or seizing the STEEM / vests from certain accounts that ninja-mined comes to mind. It's a sub-optimal solution because if someone ninjamined and then transferred prior to this, they'd keep the STEEM. Again, I don't really favor seizing other entitity's assets unless they continually demonstrate that they are using the assets to threaten the survival of the network.
I note that freezing the stake of Tron is exactly what witnesses attempted to do, and failed.
We no longer have that ability, and unless Tron and the exchanges execute code voluntarily to prevent their governance of Steem, the blockchain remains the exclusive possession of Tron.
The ball's in Tron's court. We await their pleasure.