Pagan is a dirty word. It means country person, as does heathen.
(Little pun--as country people, eg: farmers, get their hands dirty.)
Moving on. Today the "pagan" community is reclaiming the word pagan, no? As gay people have reclaimed queer, the hip hop community has reclaimed n----r (I don't dare type it tho), and hippies reclaimed freak.
Pagan is a generic term. How could we have pagan unity when there are so many different ways to be pagan?
Indigenous religions of all nations: are they pagans? What does a Bantu have in common with a Lakota? A Maori with a Tibetan monk?
It seems, nowadays when you say pagan, people think Wiccan, which is kind of trendy right now, with high visibility in the pop media. But once you study paganism a little, your definition broadens. So some may call Hindus pagans, but then, when you study that, you realize, Hinduism doesn't really exist, or it didn't until the English colonialists invented it in the 18th-19th century. India did not exist either, nor did Africa, until white men created them out of dozens of independent nations.
So to just call their native religions paganism, kind of belittles them, IMHO.
Then if you read my favorite book: The Jesus Mysteries, whose subtitle is: Was the "Original Jesus" a Pagan God? the question just broadens, the distinction blurs. Their thesis argues that Jesus was an invention, a myth, created to be a framework for deep spiritual truths. It was brought together in the early centuries BCE and the first century CE, by Hellenized Jews (the Therapeutae, the Essenes), who had studied Plato and were familiar with the common gnostic mystery cults of the day. So here is paganism again, in this case, the dusty classic paganism that is not in vogue today.
To get unity, you have to understand that, literalists (pagan, xian, whathaveyou) will always argue dogma, rituals, books. Gnostics, those mystical magical persons, know there is an underlying truth, a perennial philosophy, that ultimately ties all belief systems together. But you have to look for inner meanings, not outer quasi-historical stories and laws written in stone.