I think the issue with burning STEEM is that it's needed for RCs to use the blockchain. I would think that the goal of nearly all the apps on the platform is to grow to a large number of users, in which case they will need a lot of SP available to make sure their users can interact with the platform. If they are burning STEEM then they won't have that, so it seems counter-productive to growth.

If we want to encourage the burning of STEEM (which I would think that we do) then perhaps we can consider adding a new mechanism where you could burn STEEM and then receive a certain amount of RCs forever going forward. This, coupled with the proposed RC delegation pools, should solve the problem I described above.