If they don't give Terry at least what Suarez got (if they don't give him more, they're in trouble too) they run the risk of looking like huge hypocrites and just a tad zenophobics. Especially, with the whole "out house, our rules" mantra.
In the Suarez case, he only was found guilty because he admitted his crime. Terry on the other had his on video. So you'd think Terry would get more of a ban, but I think he'll get 8 max.