I've covered horror and FPS, so now let's take a look at mechanics and narrative in RPGs.
Roleplaying games typically work a lot harder to construct a complex narrative than other video game genres. They also typically tend to focus a lot on the player's choices and how they affect the characters or story. But there's a balance here: giving the player too much freedom weakens the narrative, while not giving them enough makes a game that's supposedly about freedom and choice feel pretty restrictive.
Personally, I have a lot of problems with how many big RPGs handle choice - I find that they simultaneously offer too much and too little freedom. The very principle at the core of the RPG genre is the root of almost every issue.
The issue I have with almost every RPG I've ever played is that the philosophy of choice is taken too far to preserve a strong narrative. An RPG's story is typically a major catastrophic event - think Reapers destroying all sentient life in the galaxy, the sinking of an entire region to "save" the environment, dragons laying waste to the continent, or an all-consuming war - but on the road to saving the region/country/world/galaxy/universe, you can take as much time as you want to chat with villagers, look for a marginally better sword, or mine for resources. I'm told that if I don't hurry the village will be completely destroyed, and yet I can spend several game weeks wandering around gathering resources to upgrade my ship.
This is a consequence of prioritizing player freedom over strength of narrative - the developers don't want to restrict the player's choice or tell them the "right" way to play the game, but in allowing the player to do anything at any time, the urgency of the narrative is completely destroyed. Mass Effect, The Witcher, Pokémon, Guild Wars 2, Skyrim, whatever - you can pretty much name any RPG and this will be a core issue interfering with the consistency and credibility of the game world
On the other hand, there is the occasional game that does it right. I didn't notice on my playthrough, but I have a friend who recently played through Deus Ex: Human Revolution who told me about how he got a bunch of hostages killed. Basically, your character, Adam Jensen, has recently been through an extremely traumatic attack and had most of his body replaced with cybernetics in order to save his life. In his first day back on the job, just as he's settling back in to your position as chief security officer for a major biotech firm, he gets a call requesting that he meet with the boss right away. So my friend figures it's an RPG, he can wait, he'll explore the building and settle into things. It's his first day back after being blown to pieces, after all. He gets another call, much more urgent. Something about a hostage situation at one of their facilities. Again, he figures he'll get to it when he's done looking around.
And then he gets a third call from the boss, furious, telling him that since he's waited so long, all the hostages are dead.
My friend felt that there was a bit of an issue here in that the urgency of the situation wasn't properly communicated to him. But it's also a nice kick in the butt, telling you that yes, in this game there are consequences for your actions, even if your chosen action is to not do anything. And it's something I wish more RPGs would work in.
Dragon Age: Origins tries something a bit different than Deus Ex. As you progress through the story, the growing Blight encompasses more and more of the country, preventing you from accessing certain towns and outposts as they're completely overwhelmed by the darkspawn. It helps emphasize that the Blight is a real country-spanning problem, and that it'll take a large-scale effort to push it back.
The funny thing is that this technique was stronger before all the DLC was released. Dragon Age received a few DLC packs that added new locations and quests and characters to the world, but don't advance the timeline since they're side quests rather than additions to the storyline. The fact that these missions can be done at any time means that you can start the game, play through some of the story, see that the darkspawn are moving quickly and taking over the country... and then spend days wandering the country recruiting new party members as the darkspawn wait patiently for you to come back to the main story. It's interesting to note that this wasn't really a problem with the initial release, but was introduced and made worse with DLC packs.
To take things in a slightly different direction, it's also interesting to note that while many RPGs tell you that you can be whoever you want and create your own unique character through the choices you make, you actually have very little freedom in many respects. Your choices tend to be binary, and you rarely get the chance to justify those choices to other characters. The Deus Ex games are by far the best I've ever seen at giving you a variety of options in terms of both gameplay and narrative direction, and seem to track and comment on an absurd number of actions. Unfortunately, that's not the norm.
Finally I'd like to look at how RPGs can go both too far and not far enough, using Mass Effect and Mass Effect 2 as examples. As a third-person shooter / RPG hybrid, Mass Effect's action-packed and yet highly tactical combat brought in a lot of players who might not normally consider buying an RPG. The first game was a little too fiddly for many of those players - you got weapon and armour drops, but they were frequently exact duplicates, and the vast majority of your loot was just vendor fodder. That said, there were so many potential variations, upgrades, and slight differences that some players just didn't want to deal with all those constant numbers and comparisons.
Mass Effect 2 was streamlined and simplified, which was a good idea, but it went too far. No inventory management at all is not necessarily a problem, but what is a problem is that the guns have statistics and some are objectively just better than others, but the game doesn't tell you that - there is a best pistol, but you have to turn to the wiki if you want to know which one it is. Furthermore, the skill system was disappointing and unrewarding in a major way. At higher levels it costs more points to upgrade an ability, but you're still only earning one point per level, which means that more and more as you level up, you'll excitedly open the menu for your power boost, and get... nothing. It feels crappy to have the game reward you for every level-up early on, and then claw back those good feelings the stronger you get. That's pretty much the opposite of what you want to do.
This article is getting a little long as it is, so I'll cut it off here. You might have figured out by now that I think modern RPGs are conflicted in what they want do do and how they do it. If you're interested in reading more, I wrote another article on RPGs a while back, focusing on how they handle choices and morality.
I don't mean it to be, but I think the article comes across as a fair bit more negative than anything else I've written recently. So, with that in mind, have you played any RPGs where the mechanics and narrative cooperate to provide a great experience? If so, I want to hear about it!