In fact, in 4e, you don't need to lug around a pseudo-Templar to heal your characters!
Haha, good one. Zulgyan does have a point I think (provided you accept his highly questionable definitions of S&S and HF), but the path from S&S to HF has more twists than he makes out.
In Gygaxian D&D, the rules assumed the PCs were amoral looters, hence XP for gold. From Dragonlance onward, the default PCs were good guys. 2nd ed supported this with some rules - no xp for gold and no assassin class. This also made progression slower, making campaigns more epic.
3e brought back the assassin and level progression returned to the Gygaxian rate, making the game more S&S again. 3e remained lethal and fudging was no longer implied. 3e lost 2e's emphasis on story and setting so the game had, imo, become a lot more S&S, as Zulgyan defines S&S. Characters were more interesting mechanically but interesting characters aren't a HF trope. They're a trope of good fiction.
In 4e although there are warlocks and tieflings, they are just emo. PCs are still good guys, but some wear black. In 4e it's harder to die, so the game has become a bit more HF, epic quests are better supported.
But 4e is points of light, action is the most important element, not setting. In HF, setting is of supreme importance. The epic quest is really just an excuse to show off the geography and history of the author's beloved world.
In conclusion, 2e was the high point (or nadir) of HF in D&D. 3e is slightly more HF than 1e, purely because the PCs are assumed to be good, and 4e becomes a little more HF (but still less than 2e) because epic tales are better supported than in 3e.