20 hours to level up to 10.... that is longer than most SP only games now a days. I believe one of the reviewers of another but not quite the same MMORPG said it took him 3 hours to get level 8 doing go hither quests. With a max of lvl 20, the pacing seems about right.
Missions drive the story, quests drives up profits and power. I would be afraid to complete things as quickly as possible because how long is it before an expansion will be released? I would hate to thing I would PvP for 3 months while awaiting new content.
As for a casual gamer game, try "Freespace". I play that while I am casually waiting for GW to update

. If you pay more than $20 for a new release, don't expect it to be too casual.