I actually don't think this would be the case. The nodes would probably still have prescribed how much of a stat increase they give and also what sphere you have to use - you could just pick which of the three possible stats should be increased. At least that's what I gathered.

That way, with the absurd amount of HP and Strength +4 nodes on Auron's grid, you could either put all those in Strength and make him a powerhouse or put all those in Defense and HP and make him unkillable. But you can't do the same with Lulu since her grid has a lack of "Power Sphere nodes". Instead, you can have the abundance of Magic Defense nodes in her part of the grid be Magic instead.