Little differences in the rule set can lead to huge differences in play.
That said, I think there are pretty massive differences between the 2014 and 2024 rules. From the near-universal power creep to the reduction of race to humans with funny foreheads to the ubiquity of teleport and temp hp abilities, 2024 is a very different beast.
Power creep is not a massive difference, by definition. Like...we call it power "creep" because it's a
slow process of
small steps. And the power creep is pretty damned small....and primarily centered on classes that most folks agree were clearly behind the curve relative to other classes. Like Sorcerer, Warlock, Monk, and Ranger. Or subclasses that were widely recognized as deeply flawed, like Beast Master and Battlerager.
Race in 5e has
always been, as you so pejoratively put it, "humans with funny foreheads". Or at least that's the complaint I've been hearing since before 2014. I, personally, think that what this actually shows is that GMs don't need statblocks that differ because 95%+ of their NPCs aren't actually different on the basis of their physiology. They might have a different silly voice, or pepper in some phrases or mannerisms, but in terms of what they actually do, think, feel, want, and say? Almost all are more or less human, because human GMs aren't exactly prone to xenofictional prose authorship.
Teleport effects have always been common, so I've no idea what you're talking about there?
Misty step isn't new to 5.5e, and
one subclass getting to use it a bit more often does not seem on the level you've described.
Temp HP sources?
Really? That's...I don't even know what to say. 5e has had plenty of sources. Celestial Warlock is a 5.0 subclass. The Chef feat was added in Tasha's.
False life and several other THP-granting spells have been present since 2014. Multiple 5.0 Barbarian subclasses offer THP--including options for the Storm Herald that hand those THP out to allies. Heck, I can even tell you one readily-accessible and desirable source that had them
removed in 5.5e, that being
enhance ability. It no longer has any of the quirky stat-specific effects, which I was disappointed by. (Doubly so since that's one of the rare places where spells being more open-ended is generally quite fine, as this is just magic which gives someone more ability to do what they already do, and thus mostly
not as useful to the spellcaster herself.)
You are, of course, 100% correct that the amount of text changed by something does not indicate how much of the gameplay is affected. But not one of the things you've listed here is having massive, whole-game-affecting changes. Not even the THP one, though I do agree that THP are
slightly more accessible now, that's not radically changing player tactics. (Especially since different sources of THP still don't stack, so getting 5 points from three different sources is meaningless unless you're actually chewing through those THP...which if you are, they'd just get healed post-combat anyway!)
And to be clear, I really do agree with you that a "small"
textual change can be a huge
gameplay change. E.g., if you add or remove a "not" from a sentence, that can radically change play. "A queen can move to any laterally or diagonally adjacent square, and cannot continue" becomes "A queen can move to any laterally or diagonally adjacent square, and can continue", which is what makes the modern game of "chess" as we understand it. Likewise, changing the base value of one healing surge in 4e from 1/4 of HP to, say, 1/2 or 1/8, would dramatically change the game despite technically only changing one number--and I don't think either one would actually produce a better game. I just don't think any of the changes you've described are huge gameplay changes.
