Zelda was unquestionable by everyone an Action RPG until the late 90s when every RPG newcomer that started with Diablo or Final Fantasy 7 became RPG elitists. You can go back to these magazines and see for yourself. You can also go back and see what an "Action / Adventure" game was too. Action / Adventure was a blanket term given to any game that wasn't a turn-based, sports game, or puzzle game. This would include everything from Zelda to Donkey Kong Country to Mario. The people that claim that the "Action / Adventure" is a real genre just take all the elements that make a Zelda game and apply it to the "Action / Adventure" genre. Action Adventure was never a real genre until the last few years.
RPG is a very very very broad term, there is no concrete definition for one. You also have to remember the Legend of Zelda came out in 1986 in Japan and 1987 here. In this time, there was only a handful of RPGs out. Dragon Quest, Black Onyx in Japan, and Ultima, Might & Magic and various other PC RPGs..
You also have to remember back then every game that wasn't an RPG was an arcade style game. Zelda, along with Ultima, and the other few RPGs out at the time broke this mold. There was no 1-1 stages, there was no dying and going back to the start of the game. Link is a character that continue to get stronger and stronger through the game with upgrades. From the start of the game to the end of the game Link is 20xs stronger. This only applies to RPGs back then. I know someone will bring up Experience Points, but why are experience points so important? I can name dozens of RPGs that don't use experience points, yet people don't give those games crap for it. If you think about it, experience points are a very outdated way to get stronger. When Link beats a dungeon and kills a boss, he is rewarded with another heart piece (HIT POINTS), later in the game he can get better armor that doubles his Defense, or stronger weapons that boost his Offense. How is this not an RPG?
While the combat in Zelda isn't totally stat based, why does it have to be? People today are getting way way to anal about their genres, especially when it come to Zelda, everyone has venom to spit out about that series, despite how important it is to the genre itself.
Anyone remember the term "Zelda clone" and how it applied for every single Action RPG that came out after it?
I have one question for you deniers, can anyone name me a single more important game to the Action RPG genre than The Legend of Zelda?