Come on then Callmelshmael. You posed the question.
How would you have arranged Mammalian Reproductive Biology? It's been much the same in principle for all vivipares, and has been for many thousands of species since mammals started well over a hundred million years ago! Even most non-mammal sexually reproductive creatures, apart from fish which use external fertilisation, use approximately similar mechanisms to start things off.,
So it would take a bit of improving on.
Is sex weird? No: it needs the sexes - male and female - to make more of the same. Sexual intercourse weird? Yes - in a wry sort of way!
Looking back on something I'm long past but probably enjoyed at the time, the human version* does seem bizarre, even amusing - since this thread is in the Religion category, perhaps it's another example of God's sense of humour. Thirty or forty minutes of sweaty, undignified effort by the bloke to give the woman three or four spasms whose purpose I never did discover, but which I gather are so important it's said a lot of women can even fake them.
*Bonobos mate in much the same way - missionary position and all.