Proposed: All skills you choose (versus the passive skills) are put into a pool. They are no longer tied to a specific trait line versus some are adept, some master, some GM.
As you put trait points into a skill line, instead of opening up a GM trait from say marksmanship as a ranger, you open up 1 GM skill. You can take any GM skill in the pool. So if you have 2 lines up to 30, you would have 2 GM skills you can choose from. BUT, you could take ANY of the GM skills for your class. Likewise, if you had a 20 20 10 10 10 build, you have 5 adept skills but you could pick ANY of the 5 adept skills.
Make sense? If GW wants to open up build diversity, this is probably the most dramatic way you could do so without breaking the game.