FOR A GOOD RPG YOU HAVE TO MEET THESE ABSOLUTES PREQUISITES
A great title for the game that give promises of sequels like: "Eternal sunshine of the rising sun: the lost kingdoms of apathy"
A lot of great hyping memorable quotes that give wet dreams their true meaning,like:
this game will last forever,You'll never be able to play something else,the best graphics since computer gaming is born,a true hero is born to behold,this game will redifine the meaning of your existance,etc
the game has to bring new roleplaying words, like: parallax smooth shadowing,spell effects transluscant ligthning effects Tm,real time movements and action realistic movement patherns and stunt effects engine,etc
the game has to announce thousands of features that defines the true meaning of rpg, like: Unprecendented real time combat,billions of objects ,millions of possible characters,freaking absolutely huge and erormous landscape mass, absolute and infinte freedom of choices,trillions of monsters etc
Has to take at least 4 years to see the light then be postponed a least two time and has to cost millions dollars
So for a good rpg you only have to take into account what was hyped before and say More ,who cares the result the only viable achivement is Mony, a good rpg a to smell cash from every orrifice,if your fanbase is not stupid enough you can cancel the title you won't earn enough.
Now for a more serious answer I'm still working on my post for this thread
http://www.rpgcodex.com/phpBB/viewtopic.php?t=10727