Not sure it's fair to compare DOS to Portal, but ok.
In your one example I kind of like the fact that if you didn't do the quests in the correct order you can't get past the barrier. Now imagine if they hadn't had done that. How many people would have finished the game without knowing there was another quest area where you get the Enlightened Amulet? It's their way of saying 'STOP', you're not ready for this yet.
I will agree though that the traps could have been a lot better. My issue however is that some traps don't make any sense. For example if I'm the person that made the trap, and it's protecting a place I want to visit myself, how difficult have I made it for myself to get it? For this reason alone most traps are just going to have an off switch, some that may require a key, etc.
However, if I feel like solving puzzles I will play Portal. I don't play DOS for it's puzzles, so it's ok that they are not so great. If they were ... then I'm playing the wrong game.
