that are not really what they look like, but they DO have the same lables... but they all just have a + with out any of the other modifiers. and they give bonus and negatives both more often... they would be recognizable but weird.
plus a ton of non core ones, and I have seen 3e fans complain that the dragon born and teifling ruine the PHB, so I am doubting that 1e had MORE forgiving progressive players... this would be a small but not 0 sticking point
yea but no... the fighter the wizard the cleric are all there in name but don't really play at all the same saves and HD hp are all over the place... and it gets worse with the 4th core class where is the thief? as they start to look at barbarians with rage and sorcerer and warlock at all this will feel less and less D&D and more and more "someone's idea of a TTRPG, but NOT D&D"
and why so many hp... and why do all the numbers in general get so big. and on top of all that why do all the classes have the same bonus to hit?
Turn undead, fireball and magic missile? Check
again lables, but would someone looking at the turn tables and then the channel divinity see it as anything other than a name... and again Fire Ball and Magic Missile made issues from 3.5 to 5e imagine not having the intervening years... all of these are in name only.
Color codes dragons? Check.
this one I think is the best argument you have... the small number of monsters, but they still would not recognize ANY of the mechanic as coming from D&D
XP, AC, Alignment? Checks.
XP is the closest here...
AC, not anything they would recognize.
Alignment... people argued 3e gutted it and people who never played 2e claim that 5e destroyed alignment...
There is a lot on top of those things, and some are a little different, but it is obviously E&D and not something adjacent.
we can't get a consensus of MODERN 2022 players to agree on that good luck with a 1981 group that are looking at to hit charts different xp charts classes VRY diffrent