| 6d6 Fireball |
No the biggest hurdle is convincing a company that there is significant demand for new 3.5 core books out there to make it worth printing them. Of the 11 people (including myself) who I game with, only 2 don't own the 3.5 PHB. Now a company would have to market their book to get those two players or they could come up with a brand new set of rules and try to get all 11 players. Which is the better business choice?
The selling point of the any new 3.5 rules would have to be that they are the 3.5 rules. There should be no conflict between the old books and the new books.
Yet to get the existing owners of PHBs to purchase the rules again, requires that the new rules be better than the old ones.
This can be done not by changing the rules but by presenting them differently.
The current PHB is written with new players in mind. How would a rule book look if it was written with existing players in mind? Instead of a book trying to teach the game it becomes a reference book to the game.
This allows it to be smaller that the original PHB. I think there are a fair number of players who would pay $10 - $20 just for a PHB half the weight of the original. With better organisation, indexing and typography, the new PHB can also be easier and quicker to use.