Yes we want the game to change, that is the point of mmos . They are ever changing. Something like this can be done but it needs to be refined and better thought out.. No need to be a pessimist here.
Your idealism is right for sure. I think the real argument is viability rather then plausibilty. the work required to add that to the game, be it a new class from level one or an advanced class from 50+ whatever, is not realistic compared to what we've seen in the past with Bio. the sheer fact that from 50-55 we got no new class stories should speak for itself. they want to give us new content, but they have to work withing the budget they are given.
Nothing wrong with brainstorming though...that's where all the great ideas come from.