No.  A larger system with more capacity actually delivers less comfort and costs more to operate.  An air conditioner is at its least efficient when it’s first turned on.  A system with too much capacity will run in numerous short cycles, turning on and off repeatedly, therefore causing it to be less efficient.  Also, keep in mind that an air conditioner only removes humidity when it’s running, so a system with shorter run cycles doesn’t remove humidity from the air very well.  Contact a qualified professional when replacing your heating & air conditioning system.  A qualified professional technician will have the experience to ensure you have a system that best matches the capacity of your home.