So basically the complaints seem to be;
Everyone is going to equip the same abilities on every job, every time.
And, the solution being argued for is;
We need to make sure that everyone can only equip the same abilities on the same job, every time.
You offer a solution that impacts everyone's ability to enjoy this game (don't forget DoL and DoH who also make use of this system), but the complaint is based on the faulty assumption that everyone plays the same way.
I have decided I don't want to level PUG and ARC on this character. I don't care if the current popular builds require abilities from either of those jobs. I don't want to level them. I might not be as awesome as the next guy, but I am playing the way I want and I'm having fun with it. It is indeed possible to put restrictions on yourself without hindering your ability to enjoy the game, but only if your enjoyment isn't tied up with being top rank on your server or being able to clobber stuff as fast as the next guy.
And if it is tied up in that stuff, then go look at the top ranked guy and level up everything the same way he has. Nothing stopping you from doing that either.
But instead it seems some of you care so much about how everyone else is playing that you'd insist on bringing back the pigeon-hole system FFXI has, where every job has to fit neatly in its slot to get anything done, and some jobs are left out entirely.
Where's the fun in that?