You are very correct. And I am also a multi-role Cmdr.
"Scaled opposition" is a bad idea and has always been bad in any game it is tried.
The level of NPC opponents should be determined within the context of the game not by your artificial and almost meaningless "combat rating."
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I'd be happy if there was a separate skill/activity combat rank that deteriorated over active-game-only-time. But this rank ONLY affects the random interdiction opponents and reacts far faster than your main combat rating.
If you visit a Haz-Rez, you should expect high-ranked opposition regardless of your rank as you actively chose to go there. If its too much for you, head to a lo-res site. However, if you want to focus on trading/exploration/mining I think having once reached a high combat rank is a permanent handicap.
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The additional rank means that if you have not shot anything within, say 5 hours of actual online game time (NOT the real-time wall-clock timers used elsewhere) your rank starts to drop and you get easier opponents. As soon as you start shooting again, your rank starts to rise again.
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E.g. You decide to go exploring for a month so your rank drops.
If you want to fight again when you get back, you will get lower level opponents until you have got your rank up (may be good as you may be a little rusty by then).
If you don't want to fight on your return and you want to go trading, or mining, you will benefit from your lower active-combat rank and get opponents you are more likely to be able to handle in your non-combat ship.
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I'm rated as Dangerous but this has absolutely nothing to do with skill, it is just a factor of having been playing since Beta. I think this inexorable ratcheting up of the combat rank is what is causing a lot of the non-combat focused players issues. I will inevitably be ranked as Elite, it will just take a while

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Skill just means you'd probably loose less ships on the way and rise up through the ranks faster than I did.