Actually tried out Epona as well, and even going heavy might and doing a lot of barbhunting it seemed extremely weak. Have yet to try it with tradition however, but I assume that would actually be weaker.
I feel like Epona currently have two major problems. First of all it provides less faith per turn than the religious settlements pantheon (same faith per border-expand but that one actually has a border expand bonus as well), second of all I just feel like religious settlements is still way too weak, border-expansion slows down A LOT after the first 2 tiles, even with might or tradition as well as heavy culture focus, and getting 5 faith every 35 turns just isn't a very good deal.
Religious Settlements just got a big buff, and I buffed Epona to +8 from expansion. We'll see.
G