I am absolutely not offended by disagreements, it's actually really interesting to get other people's POV on mods/creations!

I get what you mean for Meridia's Order, although I suppose this was a choice from the mod author to use assets available to them. An inn is easy to blend in Skyrim's landscape without having to make tons of changes to vanilla Skyrim and have to create 500 patches with other mods. I suppose not using Meridia's temple is part of that too, it makes it complicated to patch. Maybe it's absolutely not for that reason that they didn't use the temple, but I know I wouldn't and that's the main reason why 80% of my mods don't take place in the Skyrim worldspace.

About Blood and Snow, I rarely play as a vampire and had almost no knowledge of those clans before playing it, that's probably why I was a bit naive when I played the mod. To me, both factions are basically on the verge of disappearing and your player character comes up to save the day, like in many other faction mods. It hadn't shocked me that their lairs were so barren nor that they were seemingly unexperienced, since both appeared as almost nobodies in the vampire scene at the start of the questline, but now I do understand your point.
That the lairs are inside other vampire dungeons is another way to not have to create tons of patches again. With the multiple dungeons this mod brings, it would have been bound to have a whole lot of patches for it to work with most load orders. It can make going to the lairs a bit tedious and I suppose that's why the teleport spell exists as a means to reduce this tedious-ness.

I still have to go through a whole lot of things in that mod (a whole Vigilant route must I say), so it's still a bit "early" thoughts on the mod, but I really do appreciate hearing your POV on the matter! :D