Regardless if the billion was a different way or not, it's still an unbalancing factor that can be easily fixed by removing the lp gained by exploiting the system, is it not? If someone has already banked 500k lp from that tactic even, he's 350k or more above the top max possible with this new lp system. That is gamebreaking.
Even in this thread, "I got enough for theft.." that alone is tress(20k) + theft (30k) that's 50k lp that those people didn't have to gain the normal way, and can then spend those lp on skills and other dark skills if they so desired.
Point being, players exploited the system, punish them by removing the imbalancing factors (incorrectly gained lp).