Trusted personas that keep the chain safe

I understand this to encompass also keeping and standing for the fundamental values of the chain, for example decentralization. The whole point of this blockchain experiment (at least for me) is that we want to create an improvement in the world, it's not just for crypto price go high, even if that last thing can help make things happen.

Produce blocks reliably

This one doesn't seem very important to me, or rather I see an altogether different design as more resilient. Instead of trying to achieve a fewer (by economic necessity) number of highly reliable nodes, we can have a larger number of nodes, even if any one of them is relatively less reliable, where each node can take over and cover for any downtime of another node. This would make the network as a whole highly more resilient and robust.

I also look for voluntary activity done in support of the chain, whether it's building community or building things or popularizing in some way or being engaged in discussions and offering ideas, or whatever else.