Celebrim
Legend
this last thing is I think what randomness really adds to the game: we all tend toward our preferences and can end up in ruts; randomness can pull us out of those ruts and make us reconsider those preferences in ways we never would have considered and improve play.
For me, the hardest thing about improvisation is coming up with a starting point. Long tables of things like in the back of the 1st edition DMG or in the AEG Toolbox give you a springboard to launch from. If that was all randomness was good for, it would be enough.
But I think that the main reason for using dice is to have outcomes that don't make sense. I've played Amber (diceless RPG), and the problem I had with it was that the outcomes all made sense. They were all predictable. They were limited by our imaginations and by our biases and honestly, by the system itself.
Real life isn't like that. Real life never happens in a predictable fashion. The sensible expected outcome quite often doesn't happen, and instead you get something unbelievable. That's what dice or for.
I don't know how many times I've been in discussions on EnWorld were someone will offer a proposition like, "When A happens, the result should be B. Never C.", as if the world ran on rails and so every story should to. Almost in every occassion, even though C is some wild off the wall idea that I would have never imagined, I've been able to answer, "But, can we imagine a situation where when A happens, the result is C." And in almost every case, it seemed to me that the story that results from, "A happened, and then C happened" is a more interesting one than the story, "A happened, and then B happened." because the A, then C story involved a twist. And twists are what love about stories. I love it when the story veers off in an unexpected direction, and we discover (to our horror and delight) that everything we thought we understood was wrong.
So, yeah, I probably would never make a wandering encounter table that indicated an encounter with both Frost Giants and Fire Salamanders, but, then again maybe we have a thermally active region in a cold climate - like say Yellowstone in winter or Iceland. And maybe there has been a recent volcanic eruption, which has triggered a flood or a mudslide which has disrupted a Frost Giant community. And so maybe the Frost Giants say, "Garrr... by Ymir's beard, I won't stand for this!", and set out to quiet the volcano by brute force. When they get there though, intent on freezing the mountain cold, a group of salamanders tries to thwart them.
So the PC's come upon a scene of a warband of frost giants locked in mortal combat with an army of salamanders on a steaming mud plain at the base of a smoking volcano. I think that might be a pretty cool encounter.
I might even be able to launch a module from that, because you see, if the PC's don't intervene on behalf of the Frost Giants, there is going to be another eruption - a much bigger one that the PC's may not be able to escape from in time. And probably there is some place in the mountains heart which the PC's must go that Frost Giants can't...
None of this is an attempt to disagree with you really. If anything, I'm trying to say that you are more right than you realize.