I was one of several people who wrote to The Economist correcting their Latin grammar, and it looks like the last laugh was on us--not only were we geeky enough to waste our time on this nonsense, but none of us completely agreed on the correct version. Hah! Well done.
And I don't think my suggestion was quite right. I chose the neuter plural form plura for "many," but plures would probably have been better. I think the neuter is only for things, whereas the masculine is used for people even when the gender is unknown.
Oh well. At least I got to make an idiot of myself in front of millions of readers worldwide.
Update: After conferring with Richard, we decided that a) the neuter plural was OK, since the original slogan uses the neuter, and b) I should've used ex instead of e, since it appears before a word beginning with a vowel. But this also means not one of the suggestions was right! Stupid Latin.