I think the guildleve system is set up so that, in most cases, you'll have an option of which type of quest you want to choose.
An easy and short one that you can do alone, with a small reward.
An easy and long one, that you can do alone, with a better reward.
A difficult short/long one that you need a group of people to do, with a great reward.
I think some of the guildleve option will be like this, but not all. Certainly there will be some where you don't have an option.
Or, perhaps no matter which quest you complete, it results in the same cutscene at the end.
Or maybe even the quest you take or how you choose to complete it will determine how the story progresses for your character. A choices and consequences storyline would be interesting, but maybe more difficult to pull off in an MMORPG.
Toasting makes me uncomfortable. But toast I love. Never start the day without a good piece of toast. In fact, let's toast to toast.