One of the intrinsic aspects of D&D--and RPGs in general--that makes it such a great game, is that you can customize it pretty much however you want, and play just about any kind of game. Now of course the rules themselves--especially the reward system, but also the centrality of combat and "levelling up"--facilitate certain elements more than others, which is derived from the game's roots in heroic fantasy and mythology, as well as the cultural context of 20th century America that Gary Gygax was a product of. Wizards and warriors slaying dragons, taking their loot, and becoming more and more powerful.
Now I personally have little interest in games that are focused on socio-cultural dynamics, sexuality and relationships, and prefer light to moderate amounts of politics. Elements, sure, but I like the focus to be on heroic adventure, exploration, uncovering ancient mysteries, etc. And, yes, killing dragons. But I quite like the idea of the game rules providing for more options and styles, and would greatly welcome a more open-ended approach to the core assumptions of the game.
Certainly, the game has already moved away from the strictly murderhobo model (e.g. benchmarks vs. XP for GP), and I imagine will stretch out further. But the key is that it shouldn't be, imo, either/or, but both/and. Don't change the game from one core set of themes and assumptions to another set, but expand it to enable a variety of sets, or a "mix-and-match" approach. It already does this, at least implicitly, but could more explicitly do so.
To be honest, I find myself feeling more queasy about playing at cut-throat capitalism in Monopoly than I do a hero killing monsters, because the former has a more literal correlation with the real-world and elements of it that I find exploitive and oppressive and prefer not to emulate in my own life (that is, amassing wealth and property at the expense of other real people). I see heroic fantasy as more of a mythic, non-literal exploration. Monsters aren't stand-ins for real-world creatures, but are embodiments of certain qualities that exist within us (we all have our dragons to slay, and treasure to discover). That said, it is also interesting to blend thematic elements, to play with the idea that some monsters aren't truly (or only) monstrous, just other. D&D adventures rarely involve orc or kobold children, so it could be interesting to have the PCs slaughter an orc tribe, and then find their nursery deep within the caves. What then? How does that impact what they just did, and their characters' assumptions about what a orc or kobold is?
In my opinion, the natural and healthy evolution isn't to change or narrow the themes of the game to something different, but to broaden it to facilitate more styles of game play. I would love to see a book, a "DMG 2," that's focus was playing with the core assumptions and themes of the game, providing templates for different styles of campaigns that diverge to varying degrees from the archetype.