As already stated, I m not saying it should come as subjobs. There are a lot of MMOPG (as a matter of fact, every single one of them except FFXIV) which allow some sort of customization. Be it through specializations, talents, etc.
Also, I didn't have any issue with 2.0 functionality as all my jobs were 50 before it was launched.
The hell if I know, I m not one of SE's game designer. I only know FFXIV is sorely lacking in terms of gameplay related customization options (and I also include gearing in this statement).On the topic as a whole, how would it even work?