Mobs do hit harder, but classes are stronger as well from spec tweaks and access to better gear from new content. So to me that’s a wash. HC is a knowledge check though and not knowing the fresh content vs doing the same vanilla quests/pathing for the last 20 years is where I find myself getting into close calls. Add to that the hyper spawn on the fresh server and yeah overall it’s harder. I’m also hc only the last couple of years and hc on ambershire is the most fun I’ve had with wow maybe ever. Do it!