To be honest, on occasion I'm OK with linear level design, but only when the linearity isn't contrived heavily, especially using invisible barriers. Invisible barriers are ok occasionally, but they're often done in ridiculous ways. In RAGE, when you first enter the dead city to get the defib upgrade, you end up in a freeway tunnel. You cannot escape this tunnel in any means other than a passage off to the side. The exits to the tunnel are blocked with rubble that is sometimes high enough to feasibly block you, and sometimes it's exactly the size that you should be able to jump onto it, and yet for some reason, you can't.
Sometimes, though, contrived barriers don't actually portray a problem, though this depends on the game type. TF2 has many many gates, fences, and other obstacles that should easily be rocket jumped over, but you can't. But you never notice since in TF2 there's usually a ticking timer telling you to get moving to the combat area and there's also constant combat. In contrast, when you load up the TF2 levels into the Source Filmmaker, where there is no gameplay, these things stick out like a sore thumb, and it becomes hard to record on the outskirts of the map. In RAGE, there's much more downtime, more time for you to go exploring, and this is when you start to notice these things.
Levels which convey the impression that you're in a certain environment, and ones that can be explored heavily are the nicest ones in my eyes, though. To be fair also, RAGE did good on the first part, at least in places like the Dead City. If there weren't so many contrived obstacles and invisible barriers, I'd probably like the place a whole hell of a lot more. Doom and Doom II also did good on this account, even if the level design was pretty abstract, though incorporating familiar aspects to give a sense of setting. (ie: computers for Doom 1 techbases, tall buildings packed in a loose manner in a large area for Doom 2 cities, massive caverns as well as open environments for hell)
Also, I personally think things like notes, artifacts, and those things can help certain game designs. Not doom, probably. But they work nicely in some other environments.