I happen to be really enjoying Ghosts, and adding more Prestiges, just like in Infinity Ward's last CoD, would be a really good idea.
Maybe due to the whole "10 Player Squad" system IW's got going on, it would be somewhat tricky to add more Prestiges. Since I couldn't see IW adding 10 more players for your Squad, I think the leveling should just become cumulative across all Squad Members after Prestige 10+. Keep all your Squad Members, classes, unlocks across each individual Squad Member, but if you level up to Prestige 10, level 20, all Squad Members level up to Prestige 10, level 20.
I feel that after IW released the patch that allowed all Operations to be active at any given time, leveling got a lot faster. As a veteran Call of Duty player, I was averaging around 18-20 Hours per Prestige from about Prestige 1-6. Then after that patch was released, my average time went down to 7-8 Hours from Prestige 7-10. I for one am a strong believer in leveling shouldn't be easy and quick. Yes I do probably play a bit more than the average person, but in a game like Ghosts where your level really doesn't mean anything (You can just buy everything), leveling needs to stay slow.
I was very disappointed that Treyarch didn't add any additional Prestiges with Black Ops II, so I hope you continue to add Prestiges. I mean, would it really be bad if Ghosts had say, 100 Prestiges? Like I said, level means very little in this game, so why not the more the merrier?