Despite the 12+ xp that the OP rec'd, it still bugs me. I think there are at least 3 major strands:
Dragons & Dragons
Dragons & Dungeons
Dungeons & Dungeons
Dragons & Dragons "4e" is where the mechanics presupposes/predestines heroic fantasy
Dragons & Dungeons "often 2e and sometimes 3e" is where the mechanics emulates Dungeons but the social contract and good adventure building allows PCs to rise to heroism
Dragons & Dragons assumes you are all heroes. Dragons & Dungeons enables you to have viable hope to be a hero. I find the latter much more exciting. I think heroism is boring if it feels predictable how the movie ends (defeat the monster and marry the king's daughter). I can agree that 4e is the apotheosis of Dragons play at the expense of Dungeons (dungeon delve skirmishes not included) but I cannot agree that 4E is the apotheosis of Dragons play for me. I hope I'm not in some strange minority.
Dragons & Dragons = let's pretend we are heroes
Dragons & Dungeons = let's pretend we can be heroes
Lovely. Just what this thread needed. Someone trying to redefine things so all editions
except 4e are Dungeons and Dragons.
The power level of a first level adventurer with respect to an orc hasn't changed much from 3e to 4e. And it actually takes orcs longer to kill PCs in AD&D than it does in 4e (one minute combat rounds). Unless we're talking about BECMI or pre-UA 1e fighters or, arguably, AD&D thieves, a first level PC is already a huge cut above the norm.
And in 4e PCs die - often as much as in earlier editions. A first level PC has a hard time against a battletested orc warrior just as a first level PC in earlier editions does against an ordinary orc warrior - and it takes longer for an orc to kill a first level
wizard in AD&D (one minute) than it does to kill a fully armoured fighter in 4e (5 rounds or so or about 30 seconds). It doesn't matter which D&D you play - first level and you are wet behind the ears.
The real difference in heroics isn't as you describe it. Most NPCs are near non-combatants by RAW (0th level in AD&D, commoners in 3.X, and Minions in 4e). A first level fighter in AD&D with weapon specialisation and heavy armour can chew through a lot of them. A first level cleric with Sleep in 1e or worse with two uses of Phantom Forces in 2e is seriously powerful, and the 3 spell 3e version is almost as bad and can repeat and then cast a pile of cantrips. It's that 4e PCs (other than in Eberron) live in a crapsack world, whether the Nentir Vale/PoLand, Athas, the post Spellplague Realms, or wherever. There is no Elminster, no Mordaniken, no Drizzt. No one to shelter behind or who will play backstop if this gets out of hand. The 4e worldbuilding with its Points of Light is set up so PCs try to be heroes not because they are more powerful than the surrounding world (that has always been true). They are called to be heroes
because there is no one else to do the job.