I think the reason why there is such controversy over this topic is because both sides don't realize one fundamental issue:

You are playing different games.

To the hardcore gamer, levels 1-49 are just filler. You suffer through the level grind so you can get to the endgame content with your chosen class/job combo and get awesome gear. And that awesome gear lets you get even more awesome gear from even harder challenges. This is your achievement.

To the casual gamer, leveling is the point of the game. You go on quests, you explore the world, and you experience the story. This is your achievement. But what's this? You can't get all the story before you suffer through running the same instances over and over and over and over just so you can get some gear to be powerful enough to see it? This is some sort of cruel joke.