Horizontal leveling is a joke.
I would love to be able to cross-class skills. But as it stands, there is little to no reason to do so. Even if there was, eventually everyone would have all jobs maxed, and everyone would be playing with the same min/maxed setup. Sort of like how everyone and their grandmother played with /nin in FFXI.
The fatigue system is a time sink. I'm sure everyone has seen the video?
http://www.youtube.com/watch?v=abE09-tqhoM
It sounds alright, except that there is no reason to cross-class skills, (there are very few exceptions, and most of them occur before level 16). Every job lacks definition, and cross classing them only makes it worse.
Regardless, the fatigue system isn't beneficial in any way, shape, or form - whatsoever.
The simple fact is that SE has built an invisible wall that cannot be torn down, powered through, sidestepped, or out-witted. The game literally tells us when to stop playing. Considering the stat system is decidedly bugged, I can only play DoM classes without reseting my useless stats, and becoming moderate in both DoW and DoM, instead of optimal in either. That being said, I tend to only level Thaumaturge and Conjurer. As soon as I see fatigue, I log off. I'm done dealing with it.
SE will have to get rid of this "innovative feature" before they charge me for a subscription. I'm not going to pay monthly to play a game that tells me to only play it a few hours a week. If they expect me to pay for time, I want my money's worth.
That doesn't even begin to cover the ethical issues of making the game worse for the players that actually want to play the game. I honestly don't feel that a player who only plays for an hour or two on the weekends should make as much progress. It completely takes the incentive out of playing the game.
Sorry SE, but this has to go.