As a long term 4x player, I played and enjoyed Endless Legend a LOT - but one thing i disliked was the slightly "weird" setting and "lore", didn't really click with me.
If Humankind basically is a refined and improved Endless Legend in a more familiar Earth setting, it's hard to think it will be anything but a wild sucess.
Let's face it, Firaxis and the Civilization series, is now a little like a decadent ruling dynasty that has ruled for too long, has become... lazy and bloated. CIV6 in it's end state is a bloated mess in my opinion (note that I do still like the game, maybe 7/10
). Even old champions need to work out! maybe humankind will force CIV7 to be a little more refined than CIV6? I think the high point of the series so far was CIV2 and CIV4. CIV5 = in the end better than CIV6 in my book.