It is possible to do a coin successfully with a newbie account. It is just statistics are against it. Most of the time newbie accounts are used because the dev does not not want to ruin his main account. Imagine if a dev uses his main account (with this I do not mean real identity, just his main account that he has been building up over time). This would improve trust and chances of success greatly. If a dev insists on using a newbie account, then there must a reason for it and then the community will take that into account with their risk assessment. It will be a sword over his and the coins head all the time. Chances are very good for a newbie account that such a coin gets dumped by the dev when listed. Even if a dev has many coins (which is perfectly alright by the way), using his main account will improve trust that he will not just dump and that is all assurance that the community needs.

The risk is that the coin will be listed on an exchange before the things that you mention will happen (development etc.) The dev is going to put everything into the coin in anyways to make it a success right? Then use his main account. It is not an unreasonable request.