Six points for a passing TD will make guys like Manning, Culpepper, Hasselback more valuable than the best RBs. It will also slightly reduce the value of running QBs like Vick, McNabb, Brooks, Garcia, etc. In this system QB becomes a higher priority and should be drafted a lot earlier than usual.
A pretty good game for a QB, 250 yard game with 2 TDs, results in 22 points in this system. That translates into a 100 yard 2 TD performance for a RB.
Peyton Manning will average around this amount of points game in and game out. When is the last time you saw a RB average 2200yards/22TDs over his entire career.
I kind of like this idea because it forces teams to draft QBs more strategically instead of waiting until one falls into their lap in the middle of the draft.