Many games have this curious design problem: the mechanics for PCs and NPCs cannot be the same, because it would impossibly tedious to run it that way. At least, this is true in the case of any even moderately complex system. God forbid you need to run GURPS or D&D, let alone Shadowrun. The absolute hardest part of running Shadowrun, if you are a storyteller who is also a masochist and actually does this, is to stat out all of your NPCs. Character creation in Shadowrun is an ordeal, often taking hours if not days to complete. It’s completely impractical to try and do this for your NPCs, even if you’re only statting up the big hitters. I recall the one Shadowrun game I ran (for a whopping 13 sessions) had only three or four biggies that needed stats and even they took about a week to properly make. This was complicated when one of my players hacked their cyberware and suddenly I needed a precise list of her capabilities, devices, their respective ratings and then how much Essence she had left over and so on. That was a nightmare, and it’s posed a huge barrier to running it again. And sure, there are a few example NPCs in the books that are pre-statted, but there are never enough kinds of them and they don’t work for custom antagonists. Exalted has this same problem. Please try making up an Abyssal on the fly, complete with Charms and Virtues and Ability scores. I dare you. Having tried, what I can tell you is that asymmetry between the players and your NPCs is both healthy and right.
The symmetry problem has a variety of notable solutions. Apocalypse World handles it beautifully, where NPCs do not have stats and do not get to roll. Instead, all the action centers around the players and what they do with their opposition. This is big—the mechanics themselves reinforce the notion that the players are the fundamental focus of the game. On a certain die roll, they get what they want, which is sometimes to shoot some guy dead. I am a huge fan of this when running a game, and when playing. When I’m running, it takes my attention off “how much health this guy has” so that I can worry about much more interesting things like “What is this burn-flat veteran going to do now that the player has done X?”.
In the event that your system is not designed this way, you can also just wing it, which is the approach most people take to this problem when they have to deal with Exalted or Shadowrun. But winging it can hurt your ability to surprise the players with something weird, or clever. Specificity helps bring a game to life, and I feel that when I am winging in a system that isn’t designed for it that it’s somewhat obvious. And most importantly, winging it still distracts you from the most important questions about NPCs—what they’re going to do, how and why.
The approach we take in Becoming Heroes is to have three tiers of opposition. Only the meanest, baddest, evilest guys get the same work put into them as a full-fledged character, and typically there is only one of those in a game. Every other NPC gets an abridged version of the mechanics, to help facilitate running the game. In Piece of Work we take an angle much like that of Apocalypse World, where the players have to meet a difficulty in order to overcome their opposition and if they do, then they do. This approach has many advantages, chief among them is the sense of empowerment it gives players. Not only do they gain a sense of authorship in a hit-this-number system, but they also gain the sense that they are fundamentally more important than the other entities in their world. In most cases, you want both of these sensations.
The most optimized asymmetry between PCs and NPCs is found in games without a GM. A Taste for Murder and Fiasco are the best examples of this. In GM-less games, there is an absolute and fundamental difference between PCs and NPCs. Even when another player is playing an NPC for you (as happens in Fiasco), it is understood that they’re playing a foil for you, that they’re a tool for the story and nothing more. An NPC in Shadowrun doesn’t convey that sense of relative unimportance nearly so well—they have stats, after all! And they can kill you dead with them, which I suppose is another issue for another post.