You don't need those replicated exactly. People that don't know what to do will still wipe. Surviving those a bit and giving them a bit wiggle room to recover is not a bad thing. There is already plenty going on and there is going to final coil to really put them to the test. People that don't know rot method or don't know enrage method is not clearing T2. When the renauds run loose in T7, it is a wipe.
More importantly, people need to be able to get the new content in a reasonable amount of time. Keeping things exactly as they are is simply unreasonable and unnecessary.
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Those are not tier-ed difficulty. It is really more like garuda, revisit of garuda, and hopefully final termination of garuda. SE was not doing tier-ed difficulty. SE puts stuff out at max difficulty they deem people would aceept and attempt and then checks and see how are people doing and what is the clear rate. Then when they have new content to take its plave, they reduce difficulty of the existing/older content. This is their operational model and it is plain to see clear as day. There is nothing wrong with the operational model. This turns older content into a part of the ramp of the learning curve. This really smart reuse of existing assets.
And people that want to be hardcore, should put in the time and/or prioritize their time to get at the latest content. There needs to be an incentive for urgency and desire to go at stuff first. You don't get to lolly-gag, drag your feet, and still claim to do the hardcore stuff years later. People that did in the time it was meant to be earned it and now needs to move on. Old victories are hollow, there is no need to be stuck in the past, nor do they get to sit on their laurels and lord it over everyone else. The hardcore player deserve the right to have an opportunity to earn their bragging right first, but they do not have the right to deny other players access to old/older content forever. People that don't feel need to be at the bleeding edge will get difficuly reduced older content, and if that is what they are happy with SE fine with that too and they can stay 1 or 2 major patches behind. But if those people want to shift gears they can get to the starting line quicker for the newer content. SE operational model is both fair and struck the right balance.