For me, 4e just doesn't meet my minimum levels of internal consistency and causal logic. The metagame "proud nails" of 4e are just too frequent and obvious, though at this point I frankly can't even swallow "core" D&D-isms like armor class, hit points, and "Vancian" magic, let alone be bothered to deal with AEDU.
How does it meet the minimum threshold for internal consistency and physical causal logic?
Well this is going to be a subjective answer that will or will not deliver the good depending on your mental framework.
How it passes the players at my table (and presumably for folks like me) is borne out in a few ways:
1) Two of the four people at my table were collegiate athletes and have been involved in all sorts of sports and physical endeavors throughout the entire course of their lives (martial arts, gymnastics, physical combat sports, multiple ball sports, hiking, running, weight-lifting, etc). The third is a marathon runner, cyclist, hiker, big time cross-fitter etc. The fourth is a very physical person despite not being as intensive as the other three.
All four of us are very entrenched in various spectator sports (from ball sports, to gymnastics, to combat sports). All four of us are very appreciative of the action-adventure genre and its cinematic physics.
From that rather informed perspective, the four of us all hold that 4e's dynamic combat engine hews closer to the real thing than anything else we have come across. That includes forced movement, dynamic mobility, the interaction with the battlefield/terrain that the prior 2 bring into play, marking, encounter powers, dailies, and the triggered immediate/OA aspect of play.
Further, it is abstract in just the right places so the narrative can retain needed diversity and malleability.
2) The keyword system is extremely elegant and intuitive. It informs our thoughts on fictional positioning just enough to make sense of what is happening, to adjudicate improvised actions/interactions efficiently and easily, and is broad enough in scope that (again) narrative malleability is still in play.
3) Noncombat conflict resolution is a place that is always going to be a wobbly litmus test for folks. I don't prefer much process-sim here at all. I much prefer stakes-driven play with light, abstract resolution mechanics that are predicated upon consistetnly achieving drama-based needs and genre coherency. If the resolution mechanics are transparent and robust, the PC build mechanics are properly synched with those resolution mechanics, if the agenda/principles that inform their usage are clear, and the whole of it (when deployed by proficient GMs and engaged players) yields the intended dramatic, genre-coherent conflict...then you've won the game.
In 4e, the physical causal logic is left up to the table to negotiate with advice that those drama-based DCs that scale with the PCs through the tiers match up to what you would expect. Each tier is basically a different genre. At Heroic, (where you're Boramyr) you're going to be informed by a wee bit more process-sim (but certainly more supernatural than our real world) than you are at Paragon (where you're doing ridiculous Legolas-like stuff regularly). By Epic tier, earth-based process-sim is wholly out the window as you're The Incredible Hulk. Each step of the way you move further and further away from earth-based process-sim toward supernatural genre-physics and simulation of those conceits.
I'm not only good with that, I prefer that. You have guidance on genre but each table manages their own genre credibility tests (where they "say yes, roll the dice" or look at you cockeyed if you attempt to invoke something completely off the reservation that may or may not be bad faith - which this has yet to happen in my group). I think its better for narrative malleability and table handling time in action resolution (leading to a faster-paced game). I know [MENTION=6668292]JamesonCourage[/MENTION] disagrees here (I think because it doesn't pass his minimal threshold for process-sim and this dovetails with his sense of player empowerment?) but I've yet to encounter a problem at the table due to it.
Would it have been a bit better if they would have included something akin to MHRP's progressive list of stuff you should be able to expect to do as you move along in each tier of skills? I think so. It certainly helps to inform that game. Truly, if you use the first 3 tiers for each of those abilities (d6, d8, d10), you basically have stuff for the tiers in 4e. But I think each table can figure it out on their own well enough just by referencing various genre fiction, taking in each DMGs' guidance on the tiers of play, and reading the tea leaves of each character's thematic investments (skills, power suites, Themes or PPs or EDs, etc).
If I was rewriting 4e, I would have done certain things differently in terms of layout, advice, and emphasis (and a few minor rules changes). As is though, I never found its mysteries to be remotely difficult to penetrate and I found so much of its advice to be just reformatting and D&Difying indie principles that I was already familiar with.
So what it is it about 4e that so uniquely pushes characters into fictional positioning "spaces" that allow for this kind of play? Because even having thoroughly engaged with much of [MENTION=42582]pemerton[/MENTION] 's descriptions, I still have a hard time understanding how players selecting a bunch of powers/exploits/spells drives this.
But how does 4e do it?
a) I think going back to my initial invocation of transparency and the reigning in of GM latitude being kryptonite to illusionism (and all the various analysis that followed) would be helpful here. Illusionism erodes player agency, thus deprotagonizing PCs. The inversion of that is, of course, the actualization of player agency and the protagonization of PCs.
b) I'll also refer back to a few of my other posts upthread regarding the principles and techniques of running dramatic conflict resolution. Specifcally, how the SC mechanics, and the proper running of them, protagonises each PC (with respect to their specific interests, what they have staked, and in the actualization of their thematic archetype).
c) I know some folks were turned off by their perception of the "sameness" of the way PCs looked (due to AEDU, the layout of powers, and their own inability to grok the weight and implications of the keyword system), but the robust combat resolution mechanics and the dynamic diversity in PC builds manifested archetypes extraordinarily well in actual play at the table. Even if your GM is an uncreative and tactically-inept, it will still be extremely difficult for PCs to actually manifest as "samey" within the fiction of combat.
d) Then there is the Quest system of 4e. The analogue to this in DW (an unabashed indie Story Now engine for D&D) and its bonds and alignment statement. These are player authored declarations of the thematic premises they wish to address in play. 4e works the same and while DMG1 has good guidance on them, DMG2 builds on this. This empowers players and protagonizes PCs toward the pursuit of and realization (in some emergent fashion, up, down, or other) of those thematic interests.
e) Lastly, bridging off of the above, like in DW, Race, Class (and especially)Theme, Paragon Path, and Epic Destiny serve to inform and make transparent those thematic interests. So when you're buidling your PC in either system (race, class, moves, attributes vs race, class, theme - etc - , background, attributes), your bonds, alignment statement and Quests will be a natural emergent consequence. The xp system works to induce positive feedback toward the pursuit of those interests.
Sum total, 4e bleeds fictional positioning and its prominense in the resolution of every action declaration at the table. It bleeds premise and/or high stakes in every conflict-charged scene (which should be every scene).
Those are a lot of words and they may mean very little to you. Don't know.
If you would like, when I next have time, I can revisit the Saerie from 4e and the Saerie from DW and compare how those two systems promote her fictional positioning, protagonize her/empower the player, and empower me as GM to frame action that addresses each thematic premise she has declared as important...and how we both get to actually "play to find out what happens" rather than ceding the trajectory of play to the imposition of my own will.
That may be more helpful.