I'm pretty sure he did it to utilize Surfer's ability to amp himself to untold degree (plus, Surfer's speed, strength, and durability), and he added Doom's, because Doom has a great knack for things like this (able to figure things out easily). Plus, who has more confidence than Doom (which is Gladiator's power - to make himself more powerful with more confidence)?
What I think anyway with a quick rundown...
Originally posted by DigiMark007
Seems like you should switch body/powers, since Glads body is probably more durable than SS and Surfer's powers are clearly >>> Glads. Then I feel like you have yourself a fight, because you'd get Doom's magic and tech combined with Surfer's powers and Glads' strength/durability.
See I put Glads as the "Powers" character because Glads powers are psionic in nature rather than physical, so they should carry over and directly stack with Surfer's already impressive physical attributes.