Character highlighting and world simulation are - in my opinion - not opposing each other.
In my campaign, I use some serious randomness: random encounters, random weather, random event. Heck, I do not know what happens if the PCs decide to travel from one city to another village - I roll for weather, I roll for possible encounters. Are the encounters friendly to the PCs or are they hostile? Let's ask the dice.
Then I take a few seconds and think about the encounter - why is that city patrol there, why are they hostile, friendly or neutral? What is the story behind the encounter, what do the NPCs want, why do they want that and how do they plan to achieve that?
My players know that there are no adjusted random encounters: when the dice call for a lvl-15 mountain troll, then there shows one up. The lvl-2 PCs can either run, hide, talk or attack. It is their choice. It is also their choice if they want to know where the creature comes from and why it is here. If they decide to slaughter the troll and continue their voyage - be my guests. Should they run, good luck, have fun, live for another day.
What, if they encounter an uber-evil necromancer about 10 levels mightier than they are, one PC casts a Water Bolt and instantly kills that boss, which they did? Hey, great, all the players, who were afraid to lose their characters, laughed, cheered and high-fived each other. A story they chose to investigate, a place they were not meant to go, with a big bunch of luck the world is dramatically changed and the PCs are heroes. They could have died there and they knew the risk, they took the risk. They survived, they won - why should I spoil that moment? Why should I feel bad about that?
In six years I offered less than 10 "adventures," most of the time, they learn about things happening in the world and either they try to become a part of it, or they leave it be. It is their decision.
This seems to be a pure simulation, doesn't it?
The players are not very interested in combat, they pursue different goals, most of them personally motivated. The PCs
are protagonists, and the story is all about them. Yes, the world is big, it does not wait for them. But they are a part of it - there are many stories happening in that world anytime, but this is their story, right now. They decide, which way that story takes, what the goals are, what they care about.
After all, even if I try to simulate a fantasy world as realistic as I can, I know no other campaign with more character depth and emotional participation.
In no other campaign I know, the players have the goal to build a house, to marry, to retire in a pleasant world. There is no world-saving
per se involved, still they are heroes, they are human and they are a very active part of the world and it is their story of their life.
I love Rolemaster. I. Love. Rolemaster.
A few years (2 or 3, if I am not mistaken) ago, a new player joined our campaign; he was used to Shadowrun, to The Dark Eye and to D&D. Whenever there was a combat, he stood in the first row and led the slaughter. He was, as you can possibly imagine, very into combat.
When he joined, he made a barbarian, highly specialized in melee, and in Concussion Hits. It was a real one-man-army, a two-legged-genocide. He was eager to thin out the creature population on that continent.
It needed only one simple combat and the player was shocked and called out "combat s**ks!"
He still plays that barbarian, he still enjoys combats but if given the choice, he aboids combat by all means and tries to talk and find a solution.
I GM Rolemaster, because it offers me the possibility to simulate a world as realistic as possible and still gives me the option to enjoy deep character depth and no PC background story needed.