The only downside I can see to cloning new organs from existing cells is that the new organ will be an exact replica of the original cell. Because of rejection issues the recipient should be the same as the donor, or at least a blood relative. In this case, would not the new organ be of the exact same size and characteristics of the donor. Sure the new dick would be healthier, better circulation from new veins and arteries and healthy new tissue, but I don’t see how the new organ would be any bigger, just younger and healthier.
Then, again, if cloning human tissue is anything like cloning plant material, the new clone will also be the same biological age as the cells it was cloned from, healthier, but not younger, and definitely not Bigger. I can only see the new organ as being bigger if the Stem Cells were derived from embryos sired by the recipient’s well hung brother or father.