The question asked by us about the Friar Tuck barbarian is - OK, you're a little adjustment of the story of the barbarian class. Fine - but what's the connection to the story? You can adjust a tale, or an ideology to another setting - but you should still be able to explain in what sense it's still connected - not to the mechanics, but to the older story. If you can't - it may be a good story, but it's not an adjustment - it's a new thing.
Which
story are you referring to?
If you mean "the story of the class", then for many classes it hasn't been consistent. For instance, the barbarian class is introduced in 1st ed AD&D, and is not distinguished by raging. It is much closer to what many identify as the essence of the range: lots of hp, ability to function solo in the wilderness, but not a particularly heavy hitter combat-wise (eg no weapon specialisation). Rage as the centrepiece of the barbarian is a 3E thing.
If you mean "the story of the archetype", then the lawful alignment restriction on monks limited monks beyond what the archetype would allow for, because an important part of the monastic/martial arts tradition is true neutral (I won't mention the real world religions, but in fiction certain elements of this are displayed by the Jedi). So opening up the class beyond the tradition-bound monasteries opens up the class to incorporate certain important elements of the archetype.
Look at the arguments made wrt particular classes: we don't need the ranger anymore, he can just be a fighter with outlander background, and Survival, Animal Handling, etc. skills. I'm sure you've heard these, too. Well, that can really be extended to most other classes. Clerics with armor, weapons and spells? Make them into paladins, or land druids wit a specialty in healing, and an armor feat! And barbarians? Fighters with some sort of rage feat. So I don't see people telling you how to run your game - I see people worrying that these sentiments will become so pervasive that class begins to recede or disappear for those of us who want it in, especially those who want it in as a tangible thing.
I don't see how you envisage class receding or disappearing. D&D is a class-based game. But it has always been pluralistic in its mapping of class to archetype.
For instance, as I already noted, the original barbarian overlapped heavily with the ranger. (Eg if you look through the pre-barbarian DDG, you'll see many characters with levels in ranger which, once the barbarian was introduced into the game, would be better served by barbarian levels.)
The original cleric and the original paladin are almost identical in respect of archetype - the heavily armed and armoured holy warrior who is a miracle worker.
In my 4e game, we have two "paladins". One is built as a paladin, with a multi-class that I can't remember (maybe avenger?) to get access to Athletics skill. The other is built as a fighter/cleric. The existence of these multiple pathways to the same broad archetype (heavily armoured, miracle working holy warrior) doesn't make the various classes redundant or irrelevant. And just as with the cleric and the paladin in original AD&D, there are mechanical differences between the two builds which are not very important from the perspective of archetype, but are quite important from the perspective of actual D&D play at the table.
My longest-played 2nd ed AD&D character was a S&P cleric with a strongly martial bent. In rebuilding that PC for 4e, I looked at STR cleric options, STR paladin options (with a warlord multi-class to boost healing), and warlord options. I didn't look at fighter/cleric options, but probably could have. Each build would have captured the archetype of a religious war-leader. Each would also have been mechanically different, and therefore importantly different, because D&D is a game in which mechanical minutiae matter.
An approach to D&D play which treats classes as mechanical bundles with an important but multiply flexible relationship to archetypes isn't undermining the importance of classes to D&D. It's expressing one of the most central ways in which they've been important since the game was invented.
