I have to disagree. For example: I have played FF8 for app. 1,500 hours and it was so much fun. Also, the Classics like Secret of Mana/Evermore, Terranigma, etc. take more than 10 hour for a playthrough. Gernes like Strategy and RPG are time consuming but a lot of fun.
But in one point I must agree: Too much grinding isn't good for a game. For example the Shin Megami Tensei-Games have a grinding factor like no other game thus i played so far. At some points in Persona 4 I thought i have to take a break because of the grinding.
So you have to differ between Gernes, because Action and Adventures should be a lot shorter than a Strategy or RPG game.
Best hour-ratio for a "shorter" game: 15-20 hours for a playthrough.
Best hour-ratio for a "longer" game: 40-60 hours
Best hour-ratio for a "f%&/ing long" game: 100-120 hours
