Would you be in favour of removing fatigue?
No. Fatigue system favor the casual players
How does it favor casual players? All it does is take 1/10th of the exp away from hardcore players. It doesn't help a casual player catch up, it doesn't make mechanics any clearer, it doesn't demystify stats, it slightly hinders others.
Want to know what helps casual players? Giving the opposite
of fatigue -- that is, a "rested bonus" -- you stay logged off, and you get a little exp boost.
Hardcore players are going to run circles around casuals no matter what; if you took away the ability for players to be better than others (that is, to progress at different rates), you would just start everyone at the level cap with the best gear and let them... wander aimlessly?
Nobody should be forced to conform to another's schedule in such a way; there will always be people who play more than you and people who play less than you. The best solution is to let everyone play as much as they want. It's no race, Person A's two Rank 50s are hurting your Rank 30 only as much as your Rank 20 is hurting Person C's Rank 5.
if you just play at weekends and hit fatigue, just simply switch class (which you do need instead of leveling just one).
How does making a hardcore player level several other classes even help the casual player? Are you just hoping that he'll party with you one of those times he's on a low-ranked class? Either way, he'll play more on his other class than the average casual player.
In one scenario, a casual player sits at level 20 while a hardcore gets to level 50; in the other, a casual sits at level 20 while a hardcore gets to level 43 and 30.