No, I hear your concern perfectly. I was doing Chapterhouse at 92 with a 95 tank and moving past the entry hallways wasn't always easy, pulls of 2 or 3 were typically death. Now at 100 with some raid gear, I can solo tank skeletons (as a Cleric). That level gap from then until now is huge.
CH wasn't even one of the hard ones (once you know how to do it). Grelleth 2 is a tough one though for sure, I think EW 2 is tough as well (especially if you have a high DPS grp and kill the drakes quickly). If any all group geared groups beat Grelleth 2, they should get some kind of reward
CH the zone, not the hero mission. I don't think they said anything about the missions being adjusted.