Dear Blizzard, I'll fix your raiding woes.

[challengemode]

Blizzard, you say you want to make raids more challenging to the people who want more of a challenge.
You loved Ulduar, we loved Ulduar. Do more Ulduar.
Put in optional challenge modes for normal, heroic and maybe flex. Mimiron buttons, optional enrage switches, etc.
Tie engaging in this with the Thunder/Warforging of a single item from the boss.
Perhaps clearing the entire raid's challenge modes will reward players with a raid-specific vanity pet.
Heroic Heroic modes for guilds who have Heroic on farm. Keep tuning the same, it'll be impossible to acquire forged items in the first few weeks, but eventually they'll be geared enough for them.
If a guild is raiding heroic, they'll see these challenge modes as necessary anyway.
If a guild is raiding normal, some of the better ones will enjoy the optional challenge and reward of the challenge mode.
It will make forged items more of a prestige item. Though you may run the risk of world class guilds equipping some members in 100% forged items, near the next patch cycle, but perhaps they'll welcome the slight decrease in progression time. Perhaps they shouldn't be catered to. (perhaps)
This seems like an obvious idea so maybe I'm missing some gaping problem with this model but I'd personally love to see it.

[Pebrocks The Warlock]

We are not Blizzard, this is a fansite.

[unholytestament]

So you want them to almost double the number of difficulties for raids?

I do not see that happening.

[Superlolz]

This seems like an obvious idea so maybe I'm missing some gaping problem with this model but I'd personally love to see it.

The whole development time needed to add this?
But it's so obvious so Blizzard should fire GC and hire you, you clearly have your shit together.

[Anjerith]

While Ulduar is generally regarded as being a great raid, the reality of it was that very, very few people ever saw beyond Flame Leviathan until the Icecrown Tier came out. I feel that, given this, you can neither say that Ulduar was a well received raid when it was current content, nor can you even really be taken seriously.

[Lucetia]

Blizzard, you say you want to make raids more challenging to the people who want more of a challenge.
You loved Ulduar, we loved Ulduar. Do more Ulduar.
Put in optional challenge modes for normal, heroic and maybe flex. Mimiron buttons, optional enrage switches, etc.

They already said they won't do this unless the entire instance has a theme it can fit with like Ulduar. Plus it's additional work they would have to do to ensure the activation goes off without a hitch which in turn would increase the needed amount of time before a release.

[Darsithis]

We have enough of these kind of threads around here.