TB combat vs RT combat.
Isometric PoV vs First person pov.
Diversity of gameplay style and options vs combat only game. (which translates to non-linear vs linear)
I don't see where any of those have anything to do with being an RPG or not. You can have RPGs that are isometric, sure, but you also have first person RPGs.
And the other way around, a game that is isometric, has a very diversified gameplay, non-linearity and TB combat might as well be something that is definitely not role playing game.
The only thing that truly defines "RPG" is this:
Character skills vs Player skill.
As long as this is true, we have a role playing game, as you character's skills, not the player's skills, define the outcome of any action.
The player decides which actions to take, the character ('s stats) define the outcome. It's actually pretty simple, I never quite got why there is such a heavy discussion about this.
I wouldn't even put C&C as a requirement for being an RPG. So I do consider games like Diablo (yes, even 3), ADOM, Final Fantasy, ... all as RPGs. Most of them being a sub-category of RPG, of course.
But I don't know what sub-category RPG+C&C would be.
Maybe that is the definition of CRPG for some.
Is this all specifically about
CRPGs?
Oh, that C is so annoying! Defining it becomes really impossible as it stands for "computer". What is that supposed to mean in context with an RPG? It can really be anything, from TB combat to first person (Dungeon Master, etc.). So, if there is no proper, based-on-facts-only way to define a thing, why even try? Let's just call something "RPG" if it is one. And an RPG-X-mix if it mixes X with RPG elements.
Then again, this might be a case of discussing for the sake of discussing something. What's the point, really? Might as well debate on religion.