Being very honest, the goal is for very semi-casual guilds to kill SoD raids fairly quickly, especially these level up raids. I'm sorry if your guild wants a heroic-level challenge, but SoD just isn't that. The raid that went out last week was just very overtuned and far beyond our intent for a variety of reasons I won't bore you with here.
Not to say there won't ever be anything in SoD that's hard, but we don't currently believe the "critical path" of raiding (I.e clearing the raid each week and getting good gear from it) should be hard in this version of vanilla classic. There are other versions of WoW that have very, very difficult content. In fact there are more versions of WoW than not that have very difficult content. As it stands now both Gnomer and even post-post nerf ST are vastly more challenging and require way more coordination than original WoW.
One thing we like about the various flavors of classic is that in many cases the difficulty of raiding in vanilla wow is what players create for themselves by pushing their performance in things like speed runs and the like. I think long term we'd like to do better about supporting those types of emergent playstyles, but making raids a brick wall for the average joe isn't the approach we'll likely take.
I understand if that may disappoint some folks but after several years of watching data around classic player behavior, we don't believe difficult raid content is what players actually want on this side of the WoW spectrum. Individuals and some groups may want it, but writ large most people seem to just want to chill and blast stuff with their friends and that's the goal we'd like to aim for for the average guild.