This idea won't happen. For one moment I want you all to put yourself in the shoes of a dev. You take time to create the coin. You want that coin to go far. You then give control of your working capital the premine to a third party. That third party runs off with all your funds. Or that third party decides your reasoning for withdrawing funds from escrow isn't good enough and it adversely affects the coin and it dies. These are just a few reasons why no dev on earth is going to willing give up control of a premine. I am guessing there are 100s of other reasons.
I disagree, it's really no different than the IPO guidelines set forth by Poloniex. It will not hinder the developer, but will mean a great deal to investors. Looking forward to seeing the first new coin listed with "[Escrowed Premine]" in the title.
He who controls the premine controls the coin. Ok lets say polo is holding the premine in escrow. I am the dev. I say polo I need to withdraw 100 of that 150000 premine to pay for a translation. They say no. Where does that leave the dev? Or they say ok. Then come to find out the 100 coin for the translation was sent to the devs other wallet address. There are a million ways to skim off the top of a premine. Who holds it is of little concern. Anyone including an exchange could run off with it.
There is an old saying trust me with your life but not your money or your wife. Now how many devs are going to trust someone with that money?
Small premine to cover only bounties plus Foundation wallets are the answer. Make a small premine only enough to cover starting bounties only then 1% of each block. Show those set bounties. People get that and can get on board with that.