I think it looks great, it's just a spiritual successor (like a spin off).
A key aspect of the recent far cry games was the hunting side, so they've appeared to make a game based around that - I'd imagine there will be a Witcher 3 style 'tracking system' - hunting large prey, fighting other tribes & becoming a chieftain type figure.
They will continue the normal Far Cry series, that will be Far Cry 5 - this is just a side project.
Don't get me wrong, I'm not writing the game off completely. And to be honest, I don't really want them to continue "standard" Far Cry as I'm rather bored with the series.
I'm just worried that Primal will feel exactly the same as a stripped down FC4 with a different skin. Also, I'm not exactly sure how the plot will work in this one.