They'd also use clever geometry to guide the eye toward important sights. A plank sticking out of a pile of debris can do wonders for guiding the viewer
This "cleverness" of HL2 is what ruined it for me. The environment felt heavily contrived, and destroyed my desire to explore, because I felt funnelled. It was worse than what came before, because before, exploring was rewarded by finding nooks and crannies, and hidden passages. With HL2, increasingly you were forced to find the alternative routes (when the main path was blocked), which killed my desire to look for them.
See and I feel somewhat opposite, so I love that we have such a diversity of choice in games. For me I've always had a hard time getting into games where there was a ton of pointless stuff lying around. Like a game that lets you pick up a wooden fork from someone's table... is this going to be important later? Why else would they let me pick it up? I'm going to take it because it must be worth something. And it's still in my inventory when I finish the game. Ooh, a book I can read in the game, must be important... nope, it's just a story you can read, because I guess the story of the game isn't good enough to keep players interested.
Games like Skyrim and GTA I like because most of the time the stuff you find hidden here and there are interesting things happening in every corner you look. But some of the modern takes on CRPGs like Divinity: Original Sin, I have a hard time with. They encourage you in tooltips and loading screens to talk to everyone, try to trade with everyone, because some random person might be super important. But 90% of them are useless. So I waste how much time searching empty chests and pointless NPCs to find maybe one out of 100 that's actually important?
I don't like 100% on-rails stuff, but I do like a little guidance. I don't play games to waste time, I play games to be entertained. I really liked HL2's guidance. It's one of those games where you play it as a cinematic experience, not to explore an vast and complex world. There are plenty of games on both sides of the coin.
HL2 made heavy use of going the "path less traveled" to find drop boxes and ammo stashes.
In fact, there were parts of the game that told an "ambient story" that were totally skippable during the driving scene along the coastal highway. The only reason you get out of the car is if your curiosity to see what's in that damn house gets the better of you. Otherwise it is total inconsequential.
