Disclaimer: I'm just expressing my view, and how I experience things; this post is entirely biased, and I readily admit that others will experience things contrary to what I say, and thus nothing I write here should be taken as a declaration of universal truth or theoretically superior take on how to play the game.
I
really dislike the idea of the PCs as protagonists being the assumption. If it is assumed, you get PC/NPC disparity (what my players and I might call "inconsistencies") within the mechanics. I dislike the idea that the mechanics address PCs and NPCs differently. This is obviously not universally shared in game design, but it's definitely my take on it.
I'd like consistent rules between PCs and NPCs. And not "consistent rules for PCs" and "consistent rules for NPCs", but truly consistent rules for both. I want the rules to do this to aid in clarity for everyone involved. That is, the players know if something is possible/impossible, and it gives them a frame of reference for what they can expect within the fiction of the game world, providing less reason to be pulled out of immersion.
I also dislike mechanics that aim for any "cinematic" feel, or any mechanic that follows the so-called "rule of cool." While I understand these mechanics, they do nothing for me. They do not make me feel awesome. They might produce neat or cool scenes, sure. I will probably derive enjoyment from them, though odds are it'll lessen with time and frequency (such is the way of many things, I suppose).
That's why I prefer a certain amount of randomness to determine when things are "cinematic" or not. It also aids in tension. For example, critical hits (with a damage multiplier) serve this goal well. When you can't rely on the ability, the tension builds, creating a greater enjoyment payoff when the effect works or appears. If a PC is down, one is sent running, and you're the last guy between the orc warchief and the sage PC, getting that critical hit and downing the bad guy is pretty epic.
Now, if I can "I get a critical hit" now (some PrC from 3.X, daily's from 4e, etc.), it still feels cool. There was tension, and I won the day with my ability. I feel good. It's enjoyable. It's just not as epic. I've described the scene that happened relatively recently where a regenerating PC smeared some "essence of death" (remains from an avatar of death) on his right hand, on the off chance he could get the dragon they were about to provoke to bite his hand. The opportunity never came up, but the dragon bit him, and I rolled (openly, at that) and, to our amazement, the "hit" landed on his right arm, biting off his hand at the elbow. The dragon took damage, of course, but the hit was completely random, and only had a 1 in 100 chance of landing on that hand. That was awesome. Using an ability that said "and now he bites my right hand" would be cool, and would be enjoyable. It wouldn't be near what the randomness made it, though.
I want that level of awesome. I want randomness, and tension. I don't want to dictate when and how the scene plays out, all things being equal on both sides. I want to see what happens this time. I want to see if the PCs really do survive this fight, or if the bad guy goes down to a lucky hit, or if the PCs get interrupted during their travels by a merchant, wayward prince, or group of friendly bandits.
The PCs being assumed to be the protagonists (with the game being designed with that in mind) can produce a lot of enjoyable scenes. If, however, the PCs are assumed to be characters in a story, with no great plot protection, then I'd say that they can be given tools that might elevate them to that level. However, I want time to inform me if that's the case, not the mechanics. I want to
see if the character lives to the end of the series, not assume he does. That randomness and lack of strong plot protection is key for me to immerse, to feel involved, and to feel that level of
awesome.
Say what you will of 3.5 or 4e's death and dying mechanics, the "you need to roll to avoid dying" brings on the tension. I've had those "you need to make this to live" (1 in 10 in 3.5) pop up quite a few times, and the players get this look of such excitement when they make it. You don't get that excitement from "I use my Fate Point to stabilize." There's no tension. You get the same narrative, but you don't get the same enjoyment.
But that's just me. My game preferences aren't going to fit many people. Most people, probably. That's fine. That's the beauty of the game. If 5e really does pursue the "you're the protagonists in a story of heroic fantasy!" style of presentation (with attached mechanics), I hope they're something easy to discard (like Fate Points). That way, everyone wins. I don't much care what the assumption is, as long as you can peel away the plot protection pretty easily. Some people would rather play Eddard Stark than Rand al'Thor. As always, play what you like
