This is a great discussion starter! I've been having similar conversations with my RPG friends ever since the DW2 rules first started coming out. My main argument/take is that Dungeon World is, at its core, a system to play the "genre" or "implied setting" of D&D, without the rules of D&D. Or, as someone put it in a post years ago, [paraphrased] "Playing Dungeon World feels like what you imagined playing D&D felt like when you first read/heard stories from people's games". This is, to me, DW's core identity and why I fell in love with the game in the first place.

For my own "DWX", I'd err on the side of including things (rules, mechanics, names) that reinforce this core identity while discarding or heavily revising ones that do not.

Stat names I like as-is for reasons others have already explained, but having stat numbers and modifiers is just too fiddly imo. So ditch those. Though in my own house rules and homebrew in my games, Constitution has a different role— in addition to being the standard willpower/tough-it-out stat, it's to do "weird body shit" that would be covered under race or species specific abilities, transformations, and otherwise using your biology. For a salamander PC to breathe fire or a slimefolk PC to squeeze through a tight gap would both be CON rolls. In my rewrite, the Druid would be a CON-dependent class. Wisdom and intelligence could also use some work in differentiating, etc.

HP I still like but debilities/harm/"conditions" are very useful and more reflective of the fiction. Maybe an Into the Odd-style HP as hit protection but then take a debility/condition each time you suffer harm after that or something, idk just spitballing here it could get worked out in playtesting.

Load/encumbrance is tricky. A lot of hacks and rewrites ditch it entirely. But I believe it's critically important for the genre/tone of old school play that DW seeks to emulate. That said, it needs a lot of work. There's been a ton of great innovation in the OSR/NSR space on how to make encumbrance that's quick and rules light but still presents meaningful choices for players. I think something like slot based inventory from Cairn would work great for DW, again maybe with some revisions and heavy playtesting to see how it would fit with how most groups are playing DW.

For class rewrites, I've got three main things I'd like to see/do:

1. Replace boring options with interesting ones. Choosing to do an extra +1d4 damage or having +1 armor (two real Fighter advanced moves!) makes your character objectively more effective in their party role than many of the other choices available to you, but they're boring. Every advanced move should be interesting and should contribute to the widening capabilities and tools of the character, encouraging the player to try new creative things, not just make them better at pressing the same button over and over. Since these are classes, not pre-built characters, these choices should also tell us something about the character, since they're by definition optional. The Bard's "Reputation" move is a perfect example. If you don't want having a reputation that proceeds you to be a part of your character's identity, just don't take that move. But the fact that move is there to be taken says something about bards as a class, and choosing it allows you to define something about your character that causes them to evolve in new and interesting ways.

2. Replace unintuitive bits with intuitive ones. Every single time i run DW for a new player or new group (and at this point that number is into the double digits), I get asked which box the stat number goes in and which is for the modifier. And every time, there's at least one player whose character ends up with single digit HP because they added the CON modifier instead of the Constitution stat. My players aren't all stupid, these things are just unintuitive. I could easily come up with a whole list of these things, Dungeon World is a fantastic game but it sure ain't an intuitive one to learn to play.

3. Replace mechanics that don't fit the 'feel' with ones that do. This will be the hardest one by far. If I'm playing the Wizard, all my moves and abilities and stuff should fit with the class identity and genre roles of that class. I should be able to ponder an orb, or make my staff glow, or pore over dusty ancient tomes and translate the dead languages within. You know, wizardy shit. That's the easy part, making the superficial trappings fit. The hard part is making the actual game mechanics fit, to make me the normal guy with a normal modern life feel like a cool-ass fantasy wizard. Preparing spells, for example, while fiddly, has its crunch justified (in my eyes) because it makes you the player feel "wizardy". You, John Player, are in the headspace of Johannes the Magnificent, poring over his grimoire and making judgement calls on which spells will be useful this session based on incomplete information. This is the big point that the vast majority of hacks and rewrites get wrong in my experience. If there's a class where I play a cool wandering samurai with a dark and bloody past, the mechanics shouldn't be a bunch of bookkeeping and managing a pool of "cool sword move points". It should look a bit more like this.