Never played before and have a few noobie questions.

1. Is this game good for casual people? Ill probably only get 1-3 hours in a day, since I go to school during the week, work on the weekend, and because my attention span is that of a goldfish.

2. Do I NEED Legion? I probably will end up buying it, but do I HAVE to level with it?

Thats really it. Thanks for the help