After reading up on this it seems like Jesus pussed out by taking an afternoon's crucifixion over a week's impalement. Now that's suffering. So why take crucifixion instead? Think about it.
A messiah on a cross with arms wide is a more appealing symbol than a messiah-ke-bob with a spike up his ass. Imagine the statues and symbols of the latter adorning the altars, necklaces, and shrines of the world.
Think of poor Doubting Thomas. What does he do to verify the wounds of the risen impaled Jesus? ("Until I push my fist up his gaping backside, I will not believe.") And just imagine what impalement stigmata would be like. (Padre Pio: "I've been walking funny and shitting jets of blood for a week! Praise his holy name!")
Maybe Jesus wasn't wimping out, so much as engaging in a bit of far-sighted public relations.
In ancient Rome, the term "crucifixion" could also refer to impalement. This derives in part because the term for the one portion of a cross is synonymous with the term for a stake, so that when mentioned in historical sources without specific context, the exact method of execution, whether crucifixion or impalement, can be unclear. [...] The longitudinal penetration could be through the rectum, through the vagina, or through a wound opened specifically for the occasion, such as making a transverse incision to the os sacrum. [...] The survival time on the stake is quite variedly reported, from instantly or to a few minutes to a few hours or 1 to 3 days. The Dutch overlords at Batavia, present day Jakarta, seem to have been particularly proficient in prolonging the lifetime of the impaled, one witnessing a man surviving 6 days on the stake, another hearing from local surgeons that some could survive 8 or more days.