I still stand by my point that they are just naming conventions, it's only that if you want compare what Blizzard defines normal today to the past, you gotta compare it to what Blizzard defined normal in the past. Since, like you just said, before ToC there were only raids, there's not a definition of the standard developers set before the introduction of that raid and therefore a safe comparison can not be made. And of course you can ignore 10man in wotlk, when people asked for 10 and 25mans to be equal they implicitly agreed for either 25man becoming easier (which hasn't been the case) or 10man becoming harder (which has actually been the case). Therefore, comparison between 10man normals today and back then is unfair because 10mans are no longer half a tier behind and therefore are tuned differently. Heck, raiding is indeed difficult as it is today but I see the difficulty rampup starting around Ulduar and going throughout the last two expansions. Do remember that bosses such as Yogg Saron basically brought in a new generation of bosses where coordination and high personal responsability, along with being able to perform optimally with your class, started becoming a necessity for heroic modes and that has pushed developers to introduce some of those things in heroic modes. Again, indifferent to the comparison with normal because heck, it wasn't named before that.
Pretty must all RPGs are RNG dependant actually. Drops, upgrade fails, random stat rolls, some even have crafting success. Heck, basic games from which the RPG genre was born have a constant roll of the dice for whatever action you do. I really can't see where you're coming from when you state that RPGs don't have any RNG except this game.
Do remember that from Cataclysm onwards you have never been able to buy tier pieces without raiding. They started requiring tokens in cataclysm, so you didn't have those back then. And of course it isn't normal raid worthy, it's supposed to be catchup gear which is actually higher than it has been before (normal raid previous tier). Spending valor makes it above normal raid worthy, which is also more than what could be said for the past. You keep saying it's shit but the numbers prove quite the opposite.
No, deterministic progression is not a core feature, as explained above. Heck, go look at Dungeons and Dragons rules, where you can get killed because you roll too low. And again, features are not bound to a genre, they're just how the genre happened to be developing. Its definition is what can not be changed, and they haven't, because as explained above it's still a game where you play a character which isn't you in a fantasy world (RPG) with a shitload of other people (massive multiplayer) over the internet (online). Everything else is accessory and it's their decision what to make with it.
You keep saying it's less yet when people tell you that itemlevels are higher to account for the acquisition rate to be slower you go "lalalala no they're shit no lie lol". Heck, for some classes heroic scenario gear is better than a few normal mode pieces because of itemization and you're complaining that you aren't getting enough progression outside of raiding. You do get as much as before, it just seems that you're either not casual (therefore the one heroic scenario a day is too few for you) or that you just can't see it.