Without getting technical:
- Yes, moving the MB over 1 1/2" from thumb would give an asymmetric ball a little more movement.
- Asymmetric balls are not more forgiving. Generally speaking they will flip harder off friction and could be unpredictable to a newer bowler who does not have a good understanding of ball motion as of yet. Maybe they are more forgiving in the sense that they can aid a person in hooking a ball more than a symmetric (other factors not considered).
- Without knowing specifics and only guessing, my bet is the World Beater is completely soaked with oil and has not been resurfaced recently and has lost performance, hence being good on worn out conditions.
I still stand by my original suggestion. The Blur Solid will out hook a beaten up World Beater and the Wrath and will do it cheaply compared to buying a high performance ball. Bowling This Month gave it 50 for hook rating, which is solidly in the middle of all balls on the market. Lots and lots of bang for the buck in this piece. If the bowler is worried about hook potential, make sure the pro shop drilling the new ball is given advice to drill it to be strong.