For me it's all the fault of the vocals. They've got, zero emotion. They don't even 'feel' angry, they sound harsh but are just...blah.
Add to that the instruments' tone and playing is so machine like. I love technical playing, my listening habits testify to that (bands like Car Bomb, Rings Of Saturn, Archspire, and Nevermore are all extremely technical) but it's not enough to keep me interested. Those bands I mentioned have interesting personality though. Meshuggah's feeling comes across as mechanical and percussive, but, that's their identity in the first place.
But...hey... they've got skill, and a lot of fans, so they're doing something right I guess. I totally get your soundscape sentiment.
After all this talk of Technical music...some Tech Death is in order.