As someone who's been a miner, backup witness, and now fulltime witness I fully support a smoothing of the curve of SP rewards into the backup pool. I don't think the miner slot should get an equal piece of the pie however. Because they have stakeholder votes, backup witnesses are far more likely to be active and engaged in Steem compared to miners.
Also I'd still like to hear the rationale for the 9.5% number.
9.5% APR works out to slightly less than 10% APY and was chosen for the same reason that $.99 seems much cheaper than $1.00.
Haha, got it.