What about sources other than inflation, such as has funded development since the blockchain began? Beginning to fund development via inflation has not been done for Steem, although other development has, but strictly on a voluntary basis.
A new drain on inflation may not be the best way to proceed.
I agree with others on here that most other sources won't be adequate, won't be enough. However, if we pulled inflation from all 5 categories it would have the least amount of overall effect on everyone.