A strength of this system-oriented definition of character abilities is that it supports robust tactical gaming with a wide range of technically sophisticated options. A weakness is that a large amount of purely system-to-system resolution, that doesn't need to go via the fictional positioning, undermines what is distinctive about an RPG and renders it more of a boardgame. (This is a common criticism of 4e combat. Interestingly, both 4e and Burning Wheel use movement and positioning as a key anchor point for linking the system-to-system interplay of combat mechanics to the ingame fictional situation. I can't comment on 3E in this respect; as far as classic D&D combat with its one-minute rounds is concerned, it's so abstract that I'm not sure fictional positioning matters at all to its resolution in the typical case, which is one reason why I think many D&D players regard combat as contrasting with, rather than an instance of, roleplaying.)
You'll pardon me for my abbreviated reply that doesn't address most of your post.
I don't think the criticism of 4e
combat is that it resembles a boardgame. Or least, that wouldn't be my primary criticism of it. There are bits and peices of it I don't like because it arranges the flow between system and fiction in ways I don't like, but they weren't specifically addressed by your post. Of what you do address, on the contrary, I think it is quite appropriate that an RPG make movement and positioning critically important to the resolution system it uses for tactical combat. After all, this is entirely expected from our knowledge of combat. I think that in this sense, 4e, BW, 3e, and 1e are all in agreement. I certainly don't dislike BW's attempts at more granular combat in and of itself. While you could certainly choose to forgo the position of figures in 1e if you choose to do so, you'd be ignoring pages and pages of rules describing when you could take your shield bonus, the effects of being attacked from behind, whose attack had priority at what point during the combat, who needed to charge in order to begin to engage, who could attack who and so forth. AD&D could be granular on positioning down to the foot. Again, as far as combat goes, I think that BW clearly belongs to the same genera of game as D&D - which is what you'd expect from a 'fantasy heartbreaker'.
Likewise, if we increase the scale of combat to involve larger and larger tactical scale battles with increasing numbers of agents involved in the fiction, we would expect that - even if the resolution system evolves to cope with this - it will still take into account movement and positioning as critically important parts of the resolution.
When you say that it is not important that you use Battlesystem or some other sort of system for resolving mass combat, because you could just as easily use a generic system for resolving any sort of challenge that pays no attention to movement or positioning at all, you are saying that combat doesn't contrast with climbing a mountain or convincing a king. You are quite literally saying position and movement doesn't matter. A mass combat might as well be a footrace or an attempt to seduce a noble lady in terms of what was really important to resolving it. Indeed, depending on granularity of the system we used the exact same series of dice contests might have been used - roll perception, roll insight, roll persuade, and roll atheletics in some combination and you 'win'. Each differed from the other only in the color we gave the situation, and the color we used to justify doing the exact same thing and making the exact same mechanical choices in all the situations. While color is very important, as this example makes obvious, I don't think you could claim that in this system fictional positioning mattered much to the actual system. The color determined the sort of color we provided. The system itself only determined 'pass/fail' with relatively little input from the ficitional positioning. The two things, fictional positioning and color, are each operating on their own separate streams and not passing nearly as much information between them as they might be if we differentiated the above situations by having mechanical systems that tried to incorparate the things that distinguished tactical combat from climbing a mountain from developing a relationship with a person.
I don't think people say that combat contrasts with RP because fictional positioning is less important in combat.(!!!) That is a bizarre and tortured stance to have argued yourself into. I think people believe combat contrasts with role play because its quite possible to have a combat system and a game around combat that involves no RP at all. It's called a wargame, and the heritage of wargaming is very important to D&D and most RPGs generally - especially those with an assumption that violent combat plays a large role in their story. You could quite correctly call D&D - especially OD&D and AD&D a tactical level wargame with RPing attached to it. Your stance that OD&D or AD&D had at its backbone a combat system so abstract that fictional positioning on a board was foreign to its and unrelated to its rules is ahistorical and well frankly bizarre to the point invoking incredulity. I can't understand how you hold that position or what you are trying to say in your post if you don't hold that position.
Returning to why 4e was unfavorably compared to a boardgame, it wasn't because it had highly granular combat (as if that was new). It was because many felt that 4e only cared about fictional position when it was in tactical combat, and left everything else rather abstract and optional. It was because 4e lavished attention on combat and making combat interesting in and of itself, far beyond what it did for anything else.
Now, it is of course possible to have an RPG system without a tactical combat system attached to it, and so which treats physical combat as being just another form of RP in which the actual details of terrain, weapons, and tactics do not matter. I think for example a game like Dogs in the Vineyard definately trends in that direction, and as you've just shown you can make even 4e do that in a pinch - resolving a combat with no recourse to a combat system. But I do not think you could then say that such a game paid strong attention to the details of terrain, weapons, and tactics in differentiating between them mechanically.