Itching to get back into it, but...

[ZeronosVega]

I used that website extensively.

2. The concentration skill is basically replaced by a spellcaster level check plus appropriate caster stat modifier (int for black mage, wis for white mage, etc).

4. Its more streamlined and easier to understand. There is no opposing checks. You have a set defense against combat maneuvers and a set offense.

Hmm... your point on #4 reminds me, once again, of the Saga Edition rules for save bonuses. In that system, rather than rolling for Fortitude, Reflex or Will, you have a set defense which is opposed by the attacker/caster. Likewise, certain armors and items increase different defenses, along with the standard defense score. It seems to me that Pathfinder and Saga Edition share many similar ideas. If you haven't already, I would recommend looking into the Saga Edition materials just for the sake of reading it.

Unfortunately, it is a discontinued game, so the materials will be harder to obtain.