Given that we have the class to job system for 14 jobs (even classes too a little bit) being able to take multiple paths will recreate the mess and problems that 1.0 had in the beginning before any revisions and changes. The time period when ppl said whats the difference between this and that & what really is the class "role". No one really could answer the question fully since we had so much freedom and customization that practically everything was interchangeable and nothing was unique.
Once we had the revisions and changes classes somewhat were better for solo then jobs and classes had the ability to be played differently with some customization. Jobs then were really designed to be played and used for even a more defined role then the class. i could see gladiator being able to take multiple paths since its a class and then can have a varying play style but if pld would have the same ability then the role it supposed/designed to play can change somewhat or would not be fulfilled.
Like i said before with mrd having rampage & berserk allowing it to tank then dd next, gladiator having the same thing would allow it to do the same. If SE decides to have 2 jobs per class then mrd would have the ability to tank/dd with rampage/berserk it could have warrior job to be designed to only tank the best in its way using rampage and lets say dark knight dd the best in its way using berserk.
i personally see what we have now with the class-job system is good groundwork its just that it needs to be worked on and finished so we can see the final complete product. knowing that i could/can play a said class two different ways is cool along with them being efficient in doing either task but also knowing more that the jobs that branches from them are the best at the role like none other is good too. Im eager to see how everything has changed class/job wise for 2.0 once beta hits to really see how much they have improved and how well balanced everything is.