A good player needs IMHO a sound game - which includes good timing, consistency and the ability to adjust (planfully) and be able to have more than just an A game of preferred line in store.
A good player should be able to make an educated guess for a B plan at any time.
Good spare shooting is a must. Fill frames, and you can consistently score 190+. But that's IMHO basics. Knowing how to avoid splits and ugly spares thorugh adjustments is also helpful.
A good player also needs motivation (maybe sportsmanship? At least you need a competitive spirit), concentration and dedication.
A good player needs lane and equipment intelligence: reading the lane, knowing the equipment (and when, where and how to use it), and keeping a keen eye on his/her own balls' reaction as well as the competitions'. This knowledge and the ability to read minute signals from the lanes keeps a good player ahead of trouble (and competitors), and successful in the long run. Doing one good game is not enough - you need to know how to keep the scores up.
It is IMHO not wrong to haul around tons of balls - as long as the user actually is able to use them, and they actually fulfill complementary tasks, condition- and reaction-wise.