Low magic games do tend to be much more character oriented, and IME the players have had to think much more and use sound tactics to overcome odds rather than blowing through it with obscene amounts of magic. Characters rely on their skills and knowledge, not on their nifty magical gizmos.
Dude, it's not the magic or the grim & gritty that defines tactics, character orientation, "munchkiny," or use of skills and knowledge -- it's the DM and the Players. A no-magic one-hit-kill world can skill have powergamers, munchkins, and those who don't care a whit about your precious plot and style and prefer to just roll a d20 and play a character.
THIS is as bad as the other side blaming it on incompetent or limiting DM's. A flavor is just that -- a flavor. It doesn't define a playing style. It is always the DM's and Players working as a unit that define the playing style. Making sweeping generalizations about how people play under a hit point rule and a magic system is a bit mislead.
That said, I'm on both sides. I appreciate low magic or grim & gritty rules, and I think both have their place and can run fun games. I'd like to play in a few here or there. But I'll keep comin' back to the core, because at heart I want to sling around spells and act like a hero. Low magic and grim & gritty don't have much appeal to me as a ruleset, and a bad DM (one constantly harping about munchkins, for one) can ruin it all worse than a bad core DM. I like the feel of the normal magic games, and they are no less morally ambiguous, oriented on stuff, or stratiegic and skillful than anybody's low-magic bloodfest. You don't NEED low magic to be interesting.
The main game I run now isn't low magic or grim & gritty, but the players have about three magic items as a party of 5, and there is no gold. And yet there are no special rules governing creation of magic items, or use of spells. The alignments exist. People have hp. It's normal D&D in nearly every respect, and it's still as skill-focused and character-drive as anything else.
The one detail I've changed is that the PC's, instead of getting magic items, just get magic powers. And that doesn't re-define the balance of the campaign, it just means I can hand out treasure at a more comfortable pace without underpowering the PC's for basic D&D. I don't need to re-assess the entire game system just because I don't like the idea of powers dependant mostly on items. I just change a detail, and the world works fine.
If I want magic to be awe-inspiring, I just put in an epic spell or an incantation. If I want players to feel affraid of one mook with a dagger, I give the mook seven levels of rogue and three levels of assassin.
The main difficulty I have with low magic and grim & gritty is that while they serve a valuable service, they make a mountain out of a molehill more often than not, and turn into a game that is very focused on mechanics because you're learning how to enter a different idiom. And some of their advocates will preach the good word like low magic is the saving grace of gaming and will dispel munchkinism forever, unlike normal high magic rollplaying!
I don't have any problem with the existence of these things, if you like 'em, and you have a right to like 'em. But implying that they're hollistically 'better' isn't accurate at all in my book. I like my HP, AND I can make one mook with a dagger dangerous. I like my magic, AND I can make magic inspiring, and skills useful. I can have magic shops, AND stop people from being walking armaments. I like my alignment, AND I can have moral ambiguity and doubt. WITHOUT destroying the system. That's what I prefer. I know that's not everyone's cup o'tea, and more power to them, but your method doesn't dispel munchkins any better than mine.