SBD is a good idea, but bootstrapping SBD to a wildly volatile network was a huge mistake. The SBD debt collected during the initial peaks of Steem has been greatly detrimental to the Steem network. It's been an incredibly vicious cycle of people losing confidence in SBD > witnesses offering massive discounts to Steem > pegging SBD at an enormous expense in the value of Steem > now with a high debt ratio, offer further discounts etc. This further increases the SBD debt, so on and so forth.
Not to mention the overly complex currency system. It should just be Steem. Steem Power is already redundant - just make the current Steem holding in a Steem account determine influence. SBD can be done away with.
It needs to be one token. Everything else is poor design.
Of course, keep the "Estimated value in USD" for familiarity; the rewards shown on posts can also be the same.
You are greatly overstating the magnitude of the costs. The highest the debt ratio ever got was 9% which means assuming that SBD had no original cost and was all redemeed at that moment (in fact neither was the case), the result would be an incremental 9% dilution.
In fact the cost of debt problems, overstated though they are, was only even that large because action was not taken to properly manage debt earlier into the decline, when the cost would have been extremely modest (e.g. 2% reduced to 1%). Even that is not really a pure cost, except in hindsight. When the STEEM price goes up, the opposite benefit occurs. Given balanced up and down fluctuations, there is no (or negligible) net cost.
Yup, that's what @thecryptofiend was getting at as well. It's not good in the long term to operate this way.