We should rename SBD to Steem Batman Denomination. Because it's not the currency we want, but it's the currency we need.
Whoever puts up the collateral is at risk. The blockchain puts up the collateral, so it's at risk, which is reason enough to completely unpeg SBD. It's just a theoretical risk, but still.
If SBD is unpegged, then it should also be removed from the rewards mechanism. It should just be an asset on the blockchain without new emissions. I'm fine with that.
Even setting aside any reward mechanic, we still need SBD, even if it was completely unpegging.
We need it because getting a symbol on an exchange is expensive; we should see any Steem related listings as golden. Once people buy SBD on an exchange, that's as good as onboarding because they might be inclined to get a private wallet. They'll end up on steemit.com just because they bought some SBD.
We need it because having any supply (fixed or no) is potential exchange volume. Any external trade volume is good for the blockchain.
I hope only inexperienced, unstaked users buy into the notion of "getting rid of SBD" because it seems very short sighted. Setting aside exchange listings, who knows if we'll one day want a nice asset with existing distribution in HF28 to use just for staking high CPU smart contracts or something ...