If you like doing X activity level a job from list X. If you like doing Y activity level one from list Y. If you like doing both X and Y level one or more of each or a job from list Z that can participate in both. If you like doing X activity but only enjoy playing a job that is good at Y then you're SOL. Is that pretty much the formula we're going with here?
If we didn't, why have multiple jobs at all? Why not just give everyone everything then everyone will be able to participate all the time in any role they want!.
But then again SE also implemented a wicked awesome system in this game, really unlike any other MMO...we can change jobs depending on what we feel like playing.
So it's impossible to follow different paths to reach the same point? Two jobs can't be markedly different yet achieve a similar result in the end?
Impossible is quite the stretch but it is less optimal and less efficient.
I don't really want to pull it out, but I am going to anyway.
RDM melee (collective groan) is probably the most prime example of required limitations, that result in less efficiency, but still allow for success. As a RDM I feel confident if I were in a DD capacity to say I can pull 70% of a Mainstream DD. Obviously I can not compare to one, but I am not that bad off. One thing I do is support 100% better than them. Granted the more support I do the less effective my damage is, lets say I lose 20%.
My RDM is now about half as effective as a WAR in a DD position, but providing 100% more support than that DD ever will...
What happens if we boost RDM to be a comparable DD to WAR...well WAR suddenly become as worthless job. Why bring a job that does the same amount of damage as a RDM, but is unable to support even half as well as that RDM.
Or how about RDM healing, Id wager RDM is about 80% as efficient as a WHM, but it is going to be able to provide more damage via nuking. However as a RDM's nuking goes up its support goes down lets say a RDM in a nuking capacity effectively supports @ 50% of a WHM's capability. It will still provide more elemental damage, but it isn't keeping up in support.
Lets say screw it and let RDM heal just as well as a WHM, Suddenly WHM becomes a lot less desirable. If incoming damage is low RDM can nuke, if incoming damage is high, the RDM can heal.
And suddenly you kill off the dedicated jobs (which there are more off) and hybrids become the go to options. The RDM's the BLU's the DNC's the PUP's the SMN's the SCH's. The jobs that can simply do a whole lot more at any given time. Why bring a job that can do one thing, if it is only doing that one thing as well as a job that can do a bunch of things.
This is why jobs which can do more than one task are limited in other tasks. If they were not, then what would be the point of playing anything else...