Hand Control (ease Of Opening And Closing The Hand)

Being able to close your hand easily is important for making a tight fist (for solid punches). Being able to open your hand easily is useful for relaxing the hand, blocking or parrying punches, or clinching (MMA/kickboxing). Stiff-padded gloves tend to lock you into one position (fully closed or semi-closed) whereas softer-padded gloves let you open and close effortlessly. The glove's design and also breaking in the glove can help with this.
The grip bar design can also affect how you make a fist. A perfectly-placed grab bar will be the right size (not too thick or too thin), and lets you make a tight fist with that solid "roll-of-quarters" feeling inside. It's annoying when the bar is non-existent, too soft, or too close to your fingertips.