PLing all your classes and to 50 is step number one to QUICKLY learning your job. being able to cross class abilities and also do the same on jobs kinda changes how you play a job. Knowing everything available to you and learning how each job or class effect each ability and then fine tunning everything you can use in a way that best uses all the abilities available to you is step number two. after that, you simply apply , test and determain wich jobs are best suited for wich situations. Soo in that sense PLing is actually the fastest way to become an expert in your perfered job/class. without unlocking all the abilities its a much slower process.

That being said, I do agree PLs must go. Not because noobs suck or anything stupid like that , but because the life span of the game itself is truly threatened by the retarded fast speed in wich somone can reach lvl 50, 1-50 in 3 days max, yeah, thats a bit fast lols.