Ideally getting level 60 in a week of constant grinding sounds reasonable, but I do understand that the 1-59 content is merely an obstacle to the endgame content and does need attention which is why it's going to be one of our main focuses.
Is it really necessary to have to level up from 1 to 60?
Then yeah, fun factor is a major issue. I know WoW gets around the problem through exploration but I just can't see it being pulled off on Graal without a huge amount of effort and developmental skill in both level design and graphics.