Actually, I don't normally try to defend anything RoM related... but in this instance, they would probably get sued by Blizzard for copyright infringement seeing as every good suggestion made in this thread is basically all the good things from The Burning Crusade expansion of WoW. I don't think they want a lawsuit of that magnitude.
I'm not sure I have any idea how this is even related to WoW's copyrights...
Not only do they not have a copyright on anything stated in this thread, Shaman is a class in WoW, but you cannot copyright ideas. It's simply not possible.
Hybrid classes are also not copyrighted. There are countless RPG and MMORPG titles that make use of Hybrids, Elementals, Summoned Minions, and other ideas stated in this thread.
It may be true that some of these ideas may be similar to what WoW has introduced over the years, but any information discussed in this thread is not copyright-able. It's concepts that are present in other games that aren't the same.
Back to the topic at hand...
I am all for making a sort of "putty" class that can really be shaped entirely by the secondary class. Instead of making the normal skills deal different types of elemental damage, have them as Non-Elemental damage with a passive buff to all elemental damage by 50% or so. Have a passive weapon mastery that increases all weapon damage by 30% or so. Use elite skills to boost the damage of the specific element or weapon up to match other classes. (Balancing Idea for this: Make the passive elites decrease other elemental/weapon damage to make it more emphasized)
I think a key idea for this class would be to make some passive skills that change depending on the weapon you are using.
Example:
Passive Mastery Skill: If you are using a 1-h Axe, your physical attack and magical attack will be increased by 10% and your magical attacks will penetrate 15% of your opponent's magical defense. If you are using a 2-h Staff, your physical attack speed and casting speed will be increased by 10% and your critical hit damage will be increased by 25%. If you are using a 1-h Hammer, your healing will be boosted by 50% and your critical hit rates will be increased by 15%. (NUMBERS are not REALISTIC)
You get the idea though, we have yet to get any other skills that actually alter stats depending on equipment even though some say they do.