Dragons in the heroic literature were fearsome beasts of destruction that bowed to no one, and never feared to fight with their teeth and claws, but were far from the most intelligent beings on earth.
There are many, many monsters in D&D that don't match their roots. When's the last time a goblin played a trick on someone? No, wearing studded leather armor and attacking with a morningstar isn't quite what I was thinking. No, a sneak attack with a javelin isn't quite it either.
I'm sure we can "fix" quite a few things quite easily though. Use a T-Rex with fire breath for a dragon, use gnome stats for goblins, eliminate most monsters altogether, and so on.
Same goes for the pcs. I have seeing my pcs skulk around as if this was the Rainbow Six rather than a heroic fantasy roleplaying. Real heroes almost always fought fair, and led armies at the head, instead of acting like bunch of Mosad agents seeking to eliminate terrorists.
This brings up a few things. First, much of the "source material"
does involve skulking around: Conan, Fafhrd and Gray Mouser, Robin Hood, Sigurd slaying Fafnir from his hiding place in a ditch, Bilbo sneaking around the underground goblin kingdom, etc.
Second, given the nature of dungeon adventures, breaking down doors and fighting room to room, a "Delta Force" feel is almost unavoidable. If you want to get away from dungeons, you might have more hope of a heroic feel.
Third, the game, for logistic reasons, keeps the number of combatants per battle pretty low, so we don't see our heroes leading their armies into battle, heroically holding on against all odds and restoring the morale of their troops. They have no troops, so inspiring the troops isn't an issue (or an option).
Because initiative and surprise round is so important, it's foolish not to skulk around.
One big reason surprise is so important isn't mechanical; it's the genre convention of having small, "bite size" encounters in separate rooms. You have an opportunity for surprise with every room, and an adventure is just one room after another. It's not one long clash between hundreds of soldiers; it's dozens of distinct clashes between our four heroes and a few enemies at a time.
However, I do miss things like chivalric or Homeric combats. But I can't begrudge my pcs for acting so unheroic, since it would be foolish for them to ignore the rules. Many dms would call that 'stupid' and say that they deserve to die. After all, why shouldn't the rules be optimally used?
I agree that it's poor form to just say "play heroically" when all the rules are against heroism, or to say that your players aren't "good roleplayers" if they can't/won't ignore the rules to achieve the nebulous goal of "heroic" gameplay