Category 1: World first contenders.
These people are not affected at all by the nerfs because the first wave of nerfs typically happen AFTER the world first race is over (exception: Light of Dawn, where world first kill occurred at 5%. It was widely believed that Light of Dawn was tuned for 10% nerf and it was an incredible accomplishment for Paragon to do it at 5%. Thought to be impossible at 0% with the gear available at the time). They actually benefit from the nerfs because then their alts can do more hardmodes faster and thus gear up quicker, allowing them to have a more flexible raid comp when the next race begins (not relevant for DS since it is the last patch of the expansion).
Category 2: Not world first contenders, but can clear DS before first wave of nerfs
Will still get all the gear and titles before everyone else, and like the above category, can gear up alts much faster and easier. Are not affected by nerfs for their progression because they are fast enough to beat the content before nerfs come out, even if they are nowhere close to world first.
Category 3: People who did not clear hardmodes before the first wave of nerfs
It is no longer classic WoW or BC where bosses are expected to last 3 months from first attempt to dead. Content is now released close to bug-free and almost all of the fights appear on the PTR before released. Therefore if your guild is not hardcore enough to have practiced on the PTR for months before a fight goes live, you shouldn't reasonably expect to succeed before nerfs happen. Most likely, your guild does NOT have what it takes to beat content before nerfs anyway since you don't have the dedication and/or skill to play at the level of the guilds in categories 1 and 2. You should be glad Blizzard is nerfing content for you so that you can actually defeat the bosses.
Category 4: People who aren't even trying for hardmodes and are complaining the game is 'too easy'
Makes no sense. Do hardmodes, fail, and then realize the game is not so easy.
Category 5: People who can't even kill normal madness at 15+%
You need the nerfs. These nerfs help you more than anyone else.
So can anyone come up with a legitimate reason why the nerfs are bad, other than:
1) I have cool/exclusive gear and I want to maintain the prestige
2) Our guild would've killed [insert boss here] if we had 1 more week! I swear! (99% of these claims are false)
3) The raid is too easy and I am bored (exception: if you have 8/8 H before 5% nerf).