Several things would more than likely need to happen. First, since BAB is no longer an automatic thing, then more skill points would need to be given to each class. Also, this would need to be made into something of a special skill, like SPEAK LANGUAGE -- meaning that the cost was class dependent, and a maximum of 1 rank is able to be gained at each level.
I suppose, you could do it something like this:
Class_______ - Skill Points - BAB Cost
Barbarian... - 05 + Int/lvl - 1 pt
Bard........ - 05 + Int/lvl - 2 pts
Cleric...... - 03 + Int/lvl - 3 pts
Druid....... - 05 + Int/lvl - 3 pts
Fighter..... - 03 + Int/lvl - 1 pt
Monk........ - 07 + Int/lvl - 2 pts *
Paladin..... - 03 + Int/lvl - 1 pt
Ranger...... - 05 + Int/lvl - 1 pt
Rogue....... - 09 + Int/lvl - 3 pts
Sorcerer.... - 03 + Int/lvl - 3 pts
Wizard...... - 03 + Int/lvl - 3 pts
* Monk must also pay for Attack (Hand-to-Hand)
Although, doing it this way, makes one wonder why Saves, for example, would not be handled the same way... eventually, the whole class structure would need to eb scrapped and replaced with a single 'classless' class to build your character from.
Not that this have to be a bad thing, mind you.