Guys, this is coming from a Game Freak & Game Programmer. So please understand that whether Zelda is an RPG means the world, and yet means nothing at all to me.
First of all, there is no way to 'miss' in zelda, there is no real developement going on. There are no status attacks, and you can't control any other characters in the game. And to add insult to injury, there is no 'Ultimate attack' to learn.
Now all of that is debatable as to whether it is a requirement in an RPG to begin with. I say that because, like all things, Games are developing beyond what we knew back when the term RPG was created (this is back in 1991 if I remember correctly). Now, i will take each point on its own and discuss them as I know them to be.
There is no 'miss'. This is also true for Fable (Xbox/Xbox360), yet Fable *IS* an RPG, albeit an Action RPG. However, in terms of the CLASSIC RPG, then there is ALWAYS a calculation as to wether you miss or hit.
Character developement. Well, sorry, there is no arguement to really put here. There is no 'developement' in the character known as Link. There is only acquisition of new weapons and tools, and that is TOTALLY against RPG rules. In that respect Zelda is no different to getting a new hat in Mario 64, getting a new weapon in Halo, or getting the final smash in Smash brothers. This doesn't make Zelda a bad series, but it doesn't make it an RPG either.
Status attacks. Every RPG I have ever played, even the home-brew, had status attacks. These were used to give more of a realistic tone to the game. Though they were not very damaging, they were annoying as hell to deal with if you were not prepared. Zelda, as series (yes I have played most, if not all titles of the series), does not have this element.
Controlling other characters. There are quite a few RPG's that do not follow this golden rule, but they have a balance to it. To start with, RPG's where you only conrtol 1 character, are always RPG's that let's you design the character yourself. In every Zelda game (the seagull in Windwaker does not count), you only control Link (or whatever his name would be in that version) and you cannot change how he looks (changing his shirt in Ocarina of time, does not constitute changing the character).
The ultimate attack. There is no 'Ultima', no Level 30 required skill, no acquire more items before unlocking… or anything else in that range. There are 'attacks' that you can unlock in various game titles under the Zelda title, but none of them become powerful enough to call Ultimate.
In conclusion, especially after the introduction of Ocerina of Time, the Zelda series has become less and less like the RPG people claim it to be, and more and more like a FPS/Action/Adventure game. (FPS, as in using the bow and shooting it in First Person View, don't argue with me!) Does any of this make Zelda titles any less fun or adictive? Not a chance! I am every bit as addicted to Twighlight Princess as I am to Ocerina of Time, or even to a Link to the Past. But this doesn't make the title an RPG. Sorry guys