I strongly question the original idea here. It will be very confusing to internet users. On the other hand, .COM is king followed by, if you absolutely must, .NET. .ORG for some organization purposes is sought out as are some country codes on a regional basis only. .TV and .MOBI also have some relevance and niche uses but how many big companies (or any real companies, for that matter) have you seen using .MOBI. Both on a national and, in my area, at least, local level, what's used is CompanyName.COM/mobile.
People want .COM as their extension. They often will pay a premium price for, or at least register pretty crummy to downright awful .COM names even when, say, an arguably much better and descriptive one or two word new extension or country code is available. Sometimes the .NET that they SHOULD use is even available.
While I think that endorsing this move would be a bad idea, I have found over time that governmental and law making groups such as ICANN are full of bad ideas and they implement many of them. This move wouldn't kill the original 3 extensions or the very strong country codes but it would probably murder everything else. You might just get those 'hot' .ME names that you've been lusting for without much of an auction! Someone is lusting for them; right??!