You contradict yourself here. In fact, you're all over the map on this subject. Earlier, you said the expense of having multiple ball choices was tough on juniors. Now you're saying that taking the core out of the ball would limit a bowlers option. Shell and surface are the dominant factors in ball reaction.
Having eight different ball choices with you at the lanes is, in my opinion, a sign of weakness. It means a bowler doesn't have faith in his own abilities to adapt to a shot and is building in an excuse for not performing as in "I didn't bring the right ball today". The skilled an confident bowler needs three balls most of the time, maybe a fourth plastic spare ball. Any more, the bowler's just looking for a crutch .
Don't believe in the Uzi, it just went off in my hand. I, I believe in love.