Just so we're clear, this is a fourth game, or maybe rather a spin-off, there was Disciples 3 around 2010, released by Russian studio that acquired the rights to it after Strategy First went down, it launched poorly, got relaunched poorly and had final, okay-ish version about the same moment (or rather something like two weeks after) said studio also bankrupted.
D3 was already a giant mess, they tried to introduce hex-based combat, but lift unit stats from D2 (that had no unit movement), add skills that turned the balance upside down to the mix, and then struggled to glue it together into something coherent. Liberation looks like they didn't even bother to look back at what worked and just grabbed some names for their new, cool RPG idea. I won't even get into the story, but judging by the trailers I really doubt they'll have the corny, grimdark allure of first two games.