I hear the concerns about some schools (Enchanter and Weaver) being under utilized and thus it is much harder to level those than the others, and that is something that at least I had not taken into consideration when making this proposal. That is, admittedly, not something I know how to address right off the top of my head without making major changes to structures to require a more balanced set of materials.
I also hear the concerns that Free Access or Basic Access players would be at a disadvantage under this new system, but the honest answer is that you should be at a disadvantage if you don't own a plot. Not unable to join the schools, of course, but at a disadvantage. You can play as a dragon with Basic Access and can level lairshaping, but it takes longer to do so than if you owned your own lair. These are construction schools and thus if you aren't doing construction actively, you should take longer to level the schools. I realize this isn't going to be a popular statement I just made, btw, but please remember that flame-posts will be deleted when responding.
Keep in mind that the experience-per-unit is much, much higher under the current Lairshaping system than it is under the current biped-construction system. And though you can gain experience currently in other ways, nothing you craft gives nearly the experience per unit than current construction experience, and that isn't even close to lairshaping. (It is something like double the exp per unit between making tools and making construction resources, and then double again for lairshaping.)
Also, the 20%/80% break down Amon listed above is just what is presently proposed, not set in stone. That is just how the lairshaping system is.
Unfortunately there's no way to change the system so that there is one school for bipeds for construction without making the current multiple schools obsolete. And I'm sure that no one wants to have to level all over again their construction school, so that idea is right out. ;)
But please, keep the ideas coming. Not saying we've made a decision one way or another on this, so we'll keep talking. :)