I do have 2 possible solutions that build on what you say, and they both involve the abilities you listed, but instead of giving them blanket non-miss/dodged/parried status do the following:
1) "while under the effects of misdirect or tricks of the trade, abilities x,y,z cannot be ..." because honestly we all agree the times you should be getting these are really the only time you need those abilities not to miss or be dodged/parried
2) I have a mod, http://wow.curse.com/downloads/wow-a...vengeance.aspx, that displaysin a nice little box that fills up red as well.[current ap from veng / max possible ap from veng % of max]
Now while I like this solution more it would require blizzard (maybe) to put this mod into the game as a base ui feature. But my suggestion regarding this "while your AP gained from vengeance is less than x% of the max possible gain, abilities x,y,z cannot be ..."
as an aside: to the previous question, this game has 31 possible specs (counting feral druids as 2 specs). How many people play this game? lets call it an even 11 million, that is averaged out to 360K players per spec. Blizzard does not have 300K people working for them, someone will always figure something new out about a class that a blizzard dev would never have thought of and completely change the way the spec plays. This is why things like fansites and youtube will always have a place in theorycrafting no matter what blizzard tries to implement in-game to educate new players about gear and gems and spec and glyphs.
edit: I forgot to add that THEY SHOULD MAKE DEMO NOT RESIST!!!!!
edit 2: I feel I should also add that for druids, in both of my ideas, that should not apply to the 2 extra targets it hits during berserk, or even make it so using berserk cancels that temp hit/exp gain. Having a 3 target spamable mangle for 20 seconds (25 on PTR) is just to broken even with low vengeance stacks.