You should not expect to do much pruning at the time of planting to have a quality plant. Broken branches or a loose soil ball indicate rough handling of the plant. The plant should be firmly supported by the soil. The size at the time of purchase influences the price. Often a small plant will adjust more quickly.
Most plants grow much faster when they are young.
There are advantages and disadvantages to each. The soil or medium is washed from the roots before packaging and shipping. Then the roots are wrapped with a moist medium, such as sphagnum peat, and packaged. Bare-root plants usually are limited to deciduous plants, such as roses, fruit and nut trees, and some trees and shrubs. They are ideal for mail-order purchasing because they are lightweight.