A heavy research was done before choosing NWN1 as the engine for Haze:Reborn (HR). NWN isn't perfect, the graphic is cute but dated and the tileset-based system is also cute, but very awkward. Before choosing it, I examined other game engines or games with development kits:

Conan Exiles: Limited toolset abilities. No scripting language, only base models and certain elements can be changed. In addition, no decent tutorials and the development kit is extremely high-GPU and CPU demanding, nearly impossible to work with even for someone with a relatively strong PC.

Ark Survival: Same as Conan exiles.

Unity: Will require team and a lot of graphic designers.

HeroEngine: Too expensive and no reason why not to use Unity instead now that Unity has incorporated multiplayer.

Unreal Engine: Same reason as in Unity

Arma3: Arma 3 is not meant for medieval fantasy, however in the past I considered Arma 3 for another hardcore role-playing project; yet there are two major disadvantages:

1) There are no female models in Arma 3

2) Terrain editing is not intuitive and requires all sorts of plugins and additional software/s.

Arma 3 does have a decent scripting language and terrific modding abilities.

NWN2: NWN2 is practically as good as NWN1 in terms of functionality, I personally don't like the graphics style and the models, "too airbrushy".

Ultimately, NWN1 is simply the best choice, and is now out in mobile thanks to beamdog which is definitely a plus (I use it to testing the module while away from the computer).