I'd say the content is still fairly limited. I haven't done Mistlands yet. But honestly I can't imagine it to do anything significantly different or better than the other biomes? Burial chambers are still fairly repetitive, as are crypts, the random building/structure spawns in the biomes and how each biome generally looks like. If you have seen one Meadows, one Black Forest, one Swamp and so on you should have seen most or all that there is to the respective biome. There really isn't much new or exciting to discover per-se after you have explored each kind of biome initially.

Unless I really still haven't seen some sudden spike in content and new variations to the procedural generation in some other biome yet?

So if you can't find appetite in the building system or in grinding away for resources... and feel significantly bothered by seeing another Meadows, another Black Forest, another Swamp etc. that look and feel all same-y... then no, this game is still probably not for you. Or at least won't keep you entertained for long. I think it really stands and falls with you being motivated enough to realize building projects. If you can't enjoy that, then there is little to no point in grinding for resources other than gearing up to fight the bosses. Which is... well, kinda like how a lot of these games work. It's always either build stuff and set your mark upon the world, or kill stuff. But, yeah, I guess the procedural world and dungeon/cave/crypt generation could maybe deserve some more interesting things to spice it all up a bit more.