one way that would give players an incentive to prestige and not ruin the game may be to give players an additional 2.5-5 percent greater health with each prestige level. at prestige lvl 1 a player would have 102.5% health (or 105% health if treyarch wanted to be generous). a player would gain an additional 2.5%-5% helth every time they prestige so a 10th prestige would have wither 125% or 150%. it would kind of be like your character would become a "hardened" veteran over time, who was more difficult to take down. this would give some meaning to getting the achievement of taking down a person of a higher rank. in effect a 10th prestige would have jugernaut at all times, not invincible, but a little tougher to take down than some noob. (of course Jugernaut would not be a perk, otherwise there would be no incentive.)
but if hackers find a way to hack the prestige system, than their the one's who are tougher to take down.