Yeah... Taking Turns typically says it's a turn-by-turn game (uh durr?)
RPG, as people have stated, means a Role-Playing game, in such, it means any game where you have a choice of character or gameplay, and this much be a distinguished feature of the game. Halo(campaign) is not a roleplaying game, as you must be a character, and the only customization is found in the weapons you use.
Pokemon is a roleplaying game. Even though you can't change your character, and have a limited choice on what you do, you can decide your team and their attacks, which is the defining feature of Pokemon (the Pokemon, again, pretty obvious) While Pokemon is turn-by-turn it is not the defining feature.
And even in the begining Final Fantassy's they got out of common turn by turn by giving speed bars to players, which changes the order by "turn" consistantly, turning the battle system into a "Real-time" game.
The idea that RPG's are defined by a "turn-by-turn" battle system, is, absolutely, ridiculously ludicrous. I don't think that E3, IGN, Gameinformers and the like would give awards saying "Greatest RPG of the Year" away to a non-rpg game. After all, they're the experts on games. Nuff said.