You played a class that is explicitly about serving a deity, but you made her an angry atheist. I would have told you to play a barbarian.
Tell all you like, but I wanted to play a heavily-armoured divine tank warrior, not a hide-clad primal striker, so your orders are inadequate as well as pompous. Moreover, if flavour is a rule as you seem to think, you
shouldn't have advised me to play a barbarian instead, because my character is a wealthy formally educated noble with no primal or animalistic connections whatsoever. By your own logic, that advice would be unacceptable.
The mechanics were an excellent representation of what I wanted to play, the concept worked well, and the rules supported it. If I had agreed to play in a campaign with stricter rules about how you can and can't interpret class flavour, then you would have grounds to say no - but that's just changing the goal posts, and no more relevant than the fact that I actually play in a setting without gods, and therefore in context my paladin was considerably
more setting-appropriate than the default one. Without such an arbitrary rules change, with just the game as it stands, refusing a perfectly solid character concept because your own tunnel vision didn't let you see past the default flavour would certainly be a major GM fail.
I reject this. I believe that mechanics should be tied with what they are trying to represent. It doesn't mean you can't reflavor your powers, but it does mean your powers need to be more than +X to hit, +Y damage, +Z effect. If you're making a sneak attack, you're stabbing your opponent in the back, not taking advantage of an oppening to charge your weapon with ki energy to do +3d6 damage.
You say you reject it, but then you give an example which is a perfectly valid way to re-invent sneak attack, and is
not just +X to hit, +Y damage, +Z effect. By doing that, you
have tied the mechanics to what they are supposed to represent. The only reason that I'm apparently not allowed to do thing B instead of thing A is because you said so - there is nothing in the rules to indicate that you are correct, and in fact the very first books say you're not.
Unless I'm misreading you - are you trying to say that +X to hit, +Y damage, +Z effect can only represent one single flavour of attack in the entire game? But in that case, you're totally barking up the wrong tree. 4e is not a game of specific, fiddly, unique mechanics for each different effect - the mechanics are broad and robust, designed to represent multiple diverse ideas even if the numbers and effects are completely identical. Personally I would not have it any other way.
I can't help but wonder, is this really all about names? There is literally only one way in which my paladin goes againt the default prescription, and that's following an ideal instead of a deity - the rest is unconventional, but not contrary to the example. If I called my paladin some other name, like a crusader or an avatar or something, is there no longer a problem? What if the rogue renames himself to a Shinobi and changes "Sneak Attack" to "Snake Form Assassin Strike"? All of these are permitted in 4e, and why not? It's not as if anybody in the game uses the attack names - hell, I think most classes go without ever being mentioned by name, except maybe as the generic use of the term (knight = some noble dude in full plate, mage = arcane spell guy, barbarian = I'm a snobby racist, etc.). Names in 4e are entirely metagame terms, every bit as malleable as power flavour text and class descriptions.