Burning steem with SBD makes sense to our ecosystem as I see it.
As you say there are many considerations that need to be decided so that it is done correctly.

10 % of the Steem inflation accumulates on the @steem.dao account in the form of SBD. There are 3.3 million of them accumulated so far and it will continue to be filled up.
So one of the purposes we should have is that it is possible to burn the Steem using the DAO account, if we only spent 5% of incoming funds in the future it would have a major impact on our ecosystem.