I don't see coil 1-5 getting harder so... (maybe a savage mode? but I doubt they'd remove normal or anything) Only way to go is down.

That said making an "easy" version nor nerfing the instance doesn't seems very likely imo, instead it'll get easier by reason of being able to sneeze and get ilvl 250 gear some point in the future.

Or course I guess they could change it from a "raid" to be a normal instance that people go like "woot my daily coil roulette gone me T5! 5 tomes of Glowing awesome amazingness without even trying!"

But I'm guessing that'd only happen when it gets so old no one ever cares about it.