Both. When I've focused on the asc, it's ruler, moon and it's ruler and Mercury to an extent I've been able to get a good grasp on character without any recourse to the wider horoscope. I've also noticed this in the charts of the people I know. In modern astrology practice, oppositions indicate some distancing with the planet or point that is more "remote". At one point I was in a relationship with a girl who had Mercury opp. Jupiter and Venus opp. Pluto and my chart happens to have both Jupiter and Pluto strains strong.
To the concepts bit, IIRC correctly there are a number of techniques given by different astrologers over the years which mostly gear character delineation toward a few points in the chart and not much else. Lilly's manners takes planets in the 1st house, asc ruler, or any planets that are interacting with the Moon and Mercury to get a handle on personality, Ptolemy chronicled a technique whereby focus was placed primarily on Mercury and Moon, and I think Abu Mashar also focused on the ASC, Moon and Mercury paying much attention to the modality of the points in question.
Traditionally too within the chart, the houses are seen as differentiated areas of life and any planets placed within would be descriptive of that area. While in modern it seems as though the planet signifies the subjective experience that one has regarding a particular area of life. In practice, both reasons often end up aligning.
I don't typically tend to see anything from my chart as being "out there" -- I see it as all part of me. And I would probably feel like this even if I had no knowledge of astrology. But, I definitely have some trouble channeling or expressing energies in (what I view as) the best possible way. None of the planets you mentioned above are ruled by Mars, my most elevated, in my tropical chart; so it would make sense that Mars is somewhat difficult for me.
I have had a lot of violence and hatred directed toward me throughout my life, yet I still don't see this as Mars manifesting as an outside force. But maybe I am putting on the rose-colored Neptune glasses here because it's quite painful to think about. In all honesty though, I think this can be explained by other factors in the chart (not just mine, but in craft94's for example; I don't recall seeing her chart, however I'm wondering if there is some other factor that explains why she might experience Saturn more from the outside rather than in her personal conduct). In other words, I don't know that I can accept the idea that "rulership of X planet is the cause of manifestation within the personality, and non-rulership of X planet is the cause of possible external manifestation." But of course, I greatly appreciate your explanation and sources, and I can see the value in analyzing the personality by these standards. I just think there are other things to consider.
As far as my most elevated, I am either not expressing my Mars at all or I go completely overboard with it. No wonder, with it squaring my Libra ascendant. This is becoming less of a problem as I mature, but earlier in my life I did whatever I could to be viewed as lovable, beautiful, popular, sweet, good -- attractively Venusian, basically. Then when I would have an insane outburst of Mars emotion due to some injustice happening to me, many people would turn against me. Clearly their decision to accept me was dependent solely upon the Libra ASC "mask." I still don't know how to work with this Mars properly and it is admittedly an issue.
I would think, though, that the square to ASC is likely the cause of external problems rather than the lack of Mars rulerships in my chart. I don't know, this is all very subjective I guess. My main inability to accept the rulerships theory is due to the possibility of different sidereal rulerships. This is a particularly big thing for me because Mars becomes sidereal ruler of my Moon. But, then again, MEP seems to be something that is used pretty much only amongst tropical astrologers. I could be completely wrong here, just the impression I've gotten thus far.
