The criticism regarding the peg is purely based on lack of knowledge by the critic.
As stated in the whitepaper I believe, all Steem does is take a tried and proven technique from the finance/start up world - convertible Notes - and codes it into a blockchain. The simplicity of it all is genius. No need to reinvent the wheel here. In fact, its a simplified version of the Convertible Note since their aren't any discount rates, valuation caps, etc.
https://www.seedinvest.com/blog/startup-investing/how-convertible-notes-work

Also, as far as maintaining the peg with the USD, the fact that Steem doesn't have transaction fees will help immensely in that endeavor.