As the above two posters have stated, this was actually how version 1.0's ability system was handled, you had a base 'physical level' that was raised by exp the normal way, and a separate 'class rank' level, that was raised separately by 'skill points' (or SP), which was somewhat intermittently gained by using an action connected with that class, rather like FFXI. Ironically such a system is something I thought would be a good system to have but how it was handled in FFXIV 1.0.... left a lot to be desired, and it was one of the first things Yoshi changed upon taking the helm (physical level was scrapped and class rank became class level, and raised by exp).

So the old system is quite literally gone and never coming back, for good reason.