As an undergeared healer in Turn 5 of Binding Coil I had to respec all my bonus points from MND into VIT in order to survive fireball damage. As I got a new drop here and there, I was able to go back and tweak my point allotment every other week or so to slowly put some points back into MND as my new i90 gear naturally increased my VIT. Once I had enough i90 gear I was able to fully spec back into MND. We also had our OT spec out of VIT and into STR for extra DPS. In fact, our OT has switched back and forth between STR and VIT several times now.

It seems you may only be looking at this from a linear CLASS = JOB perspective. Ask people who play both SMN and SCH how they feel about both job sharing ACN's stat point allotment, and you'll start to see where this will be much more important as more jobs are added in the future.

Now this isn't to say the system is perfect or even terribly innovative, but it fills its intended purpose just fine for now.