I don't know that I completely understand the power that the trustee(s) have and what happens if all trustees colluded. But, I'm willing to reserve judgement if you think it's the best system and give it a shot.
I think that if the mechanisms are not well communicated there would be a lot of FUD that would affect initial demand/value.
The trustee has only one power, to produce blocks that conform to the rules (or not to produce said blocks).
The trustee's power is delegated from the shareholders who can revoke it at any time and appoint a new trustee.
Redundancy is possible in case trustee is compromised.
Trustee cannot change the blockchain rules.
Nodes do not trust the Trustee but validate every single transaction.
Trustee cannot create alternative chains or get away with double spend attacks.
Without a trustee all other technical solutions are attempts to do the following:
1) Randomly select someone proportional to their stake in the system... they become 'trustee for a block'.
2) Pay / Punish this person for not producing a block.
As soon as you have this random selection you simultaneously open up the network for random attacks by anonymous parties. The sheer number of hypothetical attacks that are possible under these 'random selection' processes means that the network is likely less secure and predictable. All of a sudden people start mining blocks that exclude bids/asks to their benefit or to trigger margin calls. Put another way, randomly selecting people to produce blocks gets you 'average' performance and 'random' manipulation. Delegating through your proof of stake to a trustee maximizes the predictability and fairness of the chain.
Remember, true decentralization is competition and reduction of barriers to entry.