The inflation comes from the processes that create the SBD in the first place, which is either funding the DAO or paying post rewards (when the ratio is low enough). Converting SBD to STEEM doesn't create inflation, it just changes it from one form (claim on STEEM) to another (actual STEEM). The inflation is already there, inherent in the very concept of funding things out of thin air.

If you don't like inflation then get rid of the latter (although it probably can't be completely eliminated since some witness pay probably has to come out of thin air, but it could be a lot smaller).

(FWIW I know you are in favor of this to a certain extent. I'm just commenting on the mechanisms. As long as SBD is created, via inflation in this case, it also has to be destroyed unless the STEEM value grows even faster, which arguably may happen long term–that is the premise behind inflationary rewards allegedly being a good idea–but certainly does not and happen and has not happened consistently.)