In my city, the engaged buddhists are creating an enlightened society by bypassing all that enlightening oneself first silliness. I can't wait to see it when it's finished.
With the Sangha where I live, it's more small-scale projects that are more about generating merit than trying to create an enlightened society.
The idea of enlightening oneself before trying to help out in society is interesting to me in that I'm not sure where the idea came from.
I'm not sure any of the Engaged Buddhist groups think that society will become enlightened by their efforts, most seem to be about doing the most good they can. Dharma Drum's Sheng-Yen spoke of creating a Pure Land here on earth, but that is a place that is conducive to realizations, not realizations themselves.
The earliest suttas mention doing good, little by little, to become a better person - and it was not limited to only helping out monks.
Even in the earliest of Buddhist schools, the Kassyapiyans, while Sthaviravadans, believed that realizations would come only when one's merit allowed for it. From what I've read, they were very vigorous in helping out, incidentally the Kassyapiayans eventually came to uphold both early Suttas & the Mahayana. This idea also is reflected in the story of Asanga, meditating in a cave, but not having the realization of the future Buddha Maitreya until he came out of the cave & tried to help the maggot ridden dog (by helping both the maggots & the dog).
Ultimately, the best way to earn merit is by spreading the Dharma and the best way to spread any doctrine is by being a good example.
Putting nice curtains on a sh!thole may not change the fact that it's a sh!thole, but any niceties might convince someone that there's something better to strive for than continued existence in a sh!thole.