Lolwut? Look, I really enjoy my penis. Ol' penie and me have been through a lot together. But it's not even in my top five list of most important organs.
Like, gun to my head, I have to live the rest if my life without one of; dick, heart, liver, kidneys, brain, or dermis; I'm sorry but the choice is pretty obvious
If I wanted to really push it, it's WAYYY down on the list. Like, the choice between losing my dick and one of my fingers; fine the finger goes. Between penis and the whole hand though? Sorry willy. Two fingers? Can stand to lose them. Three? Depends if it's the same hand. Any four fingers? Junk is back on the chopping block.
Gallbladder? Dunno what that even does, but my sister had hers out and she seems fine, so I think I would go with that. Pancreas? Yea, I would rather have a pancreas than a shlong
Not to mention that you can still reproduce without a foreskin, but if you were just a disembodied but otherwise intact dick-and-balls; I doubt your reproductive chances would be particularly high. So from an evolutionary standpoint, I would still argue that it isn't the most important organ.