I understand very clearly the logic of your argument. I just don't agree with it. I don't disagree with any of your examples as to whether or not those aspects of the rules of the gameworld were unintended. Yes, they were unintended. However, they were the rules of the gameworld before the rules of the gameworld were changed by the developers.
I don't think it is the job of the players to discern the intent of the developers, EVEN when something it is pretty obviously unintended. Our job, I am arguing, is to play in the world we are given, which makes these instances 'clever use of game mechanics'. You argue it is the job of the player to use their judgement and not do anything they think might be unintended, and anyone who does something that "general consensus" agrees is unintended must be a cheater and exploiter.
We are unlikely to reach agreement on this point, but I will give one example to illustrate what to me is the fundamental flaw in your assertion. In very early progession, there is no "general consensus" yet, and frankly, in any virtual world as complex as WoW, there will always be some sort of unintended consequence, especially with less tested fights. So what is a player to do? Guess? Stop playing until the developers make their intentions clear? I find the fact that Blizzard bans people for holes in their own coding to be the ultimate hypocrisy on their part. They set the world up. The onus is on them, not the player.
I realize the desire to have a "level playing field" for comparing parses on completely equal terms, but it is tilting at windmills. The layer of personal competition in terms of parse ranking is already skewed by many different things (different strats, rng, cheesing, etc) to prevent it from ever being a completely valid method for comparing player performance. I find singling out people who 'don't play by the rules as I see the rules' to be completely arbitrary, whereas if you start with the precept that the rules of the gameworld are 'the rules', then there is no more arbitrariness. Why should your standards (or anyone else's for that matter) be "the standard"?