Not for nothing but I think a lot of you are overreacting. Your suggestions to fix the problem are a bit far-fetched.
The fact of the matter is, The GH3 Les Paul was the first guitar controller to hit the scene for the PS3. It came out on october 28. As someone mentioned earlier Rock Band went gold Nov 5. There wasn't enough time to confirm that the Les Paul worked with it or not.
The reason the 360 one works is because it probably follows the standard set by the 360 X-plorer. The PS3 did not have a standard, and I don't think Activision was going to collaborate with EA to make all controllers compatible, especially considering they don't want you using any other controller in their game. Which is even more bogus than anything EA/Harmonix has done.
So theorhetically, they (Activision) could've made the PS3 guitar have a completely outrageous button mapping and it would be considered the new standard. There's really no way Harmonix could have caught this at a reasonable time. You're talking about making them go buy the game and try it out? In all honesty, why should THEY be concerned with other controllers working with their game? It was Activision/Neversoft/RedOctane that decided on the standard for PS3 guitar controllers (at least for their game- technically it's not a standard since they will block out any other non-Les Paul controller they don't make). You're putting pressure on the wrong company.
But I guess I shouldn't talk, since I don't have a PS3. But then again, I'm in the majority.