First of all, bolded part is wrong. Developers, generally, know amazingly well what genre they are creating. Skyrim is a great example of a game moving from one genre to another and was designed to be that way. It is leaning more towards the Action-Adventure spectrum, like Zelda, than towards the RPG spectrum like a Final Fantasy or Dungeons & Dragons.
Is an RPG just limited to character development and inventory management? No, of course not because Resident Evil 5 has both of those aspects but is not an RPG.
An RPG is a collection of all of the moving pieces put together in a certain way with varying weights put into each part. RPGs are known, among the game industry genres (and within the mind of the designers) to have more in depth stories than say... First Person Shooters because RPGs require the story to hold the player's long term interest instead of holding on to the short term twitch reflex and instant gratification of multiplayer FPS games.
Halo's story will, more often than not, never be put on the same level of depth as the stories found in TES, Final Fantasy or Chrono Trigger. It just won't. Even if you hold Halo up to other sci-fi genre games like Mass Effect the stories won't be on the same level of depth.
RPGs use a heavier stat based system, like D&D or Final Fantasy, because the gameplay is not based around the twitch motor skills of the player but rather the strategic mind. You're not defeating a group of Kobolds because of how well you masted the timing of pressing X, A, X, X, Quarter Circle Forward + B, you're defeating the group of Kobolds because of how well you have mapped out the battle and how well you have built your character for battle. Action RPGs change this and that is what they are designed to do, hence "action."
That is what sets RPGs out from other genres, save for Puzzle (usually), is the fact that they rely more on thought than twitch action, thus why they are more heavily stat based and why they usually have more intricate puzzles in them.
Skyrim is leaning more towards Action-Adventure because it is simply lessening the usage of stats, which cannot be denied.
Dragon Age II and Kingdom Hearts (arguably a much better example) are Action RPGs. DA II and KH still use stats to determine the damage you will do with your regular attacks, like an RPG does, but also molds it with the action genre because you can hit how often you want, dodge as well as you want, etc based on your motor skills as a player.
Is an RPG just limited to character development and inventory management? No, of course not because Resident Evil 5 has both of those aspects but is not an RPG.
An RPG is a collection of all of the moving pieces put together in a certain way with varying weights put into each part. RPGs are known, among the game industry genres (and within the mind of the designers) to have more in depth stories than say... First Person Shooters because RPGs require the story to hold the player's long term interest instead of holding on to the short term twitch reflex and instant gratification of multiplayer FPS games.
Halo's story will, more often than not, never be put on the same level of depth as the stories found in TES, Final Fantasy or Chrono Trigger. It just won't. Even if you hold Halo up to other sci-fi genre games like Mass Effect the stories won't be on the same level of depth.
RPGs use a heavier stat based system, like D&D or Final Fantasy, because the gameplay is not based around the twitch motor skills of the player but rather the strategic mind. You're not defeating a group of Kobolds because of how well you masted the timing of pressing X, A, X, X, Quarter Circle Forward + B, you're defeating the group of Kobolds because of how well you have mapped out the battle and how well you have built your character for battle. Action RPGs change this and that is what they are designed to do, hence "action."
That is what sets RPGs out from other genres, save for Puzzle (usually), is the fact that they rely more on thought than twitch action, thus why they are more heavily stat based and why they usually have more intricate puzzles in them.
Skyrim is leaning more towards Action-Adventure because it is simply lessening the usage of stats, which cannot be denied.
Dragon Age II and Kingdom Hearts (arguably a much better example) are Action RPGs. DA II and KH still use stats to determine the damage you will do with your regular attacks, like an RPG does, but also molds it with the action genre because you can hit how often you want, dodge as well as you want, etc based on your motor skills as a player.
Actually, to the bolded, yes it can be denied - even with the insistence that RPG = stats (which I don't agree with), stats still play heavily in Skyrim.
In order to be efficient at combat, you need more than just your player motor skills. You need a character that is built and specced properly for combat. The combat is based entirely around stats - weapon damage, armor damage reduction, spell cost and damage, etc...
It may have eliminated dice rolls, but stats and character build and equipment are still key components to success. Player twitch skill may play a certain part, but it is still largely character driven.

