One of the strengths of choosing a fantasy scenario, is that you have the opportunity of dragging players into the world, by creating a vibrant, living world, through events, sounds, graphics etc.
Space is much more tailored to straight 4x, simply because most of the game entities are either "technology" or basic blocks of important (planets/resources).
In fantasy games, things like culture and history are a much more integral part of the narrative. So, personallly i dont see how you would create a succesful fantasy game, be it 4x or something else, withtout working on supporting the creation of in game cultures and history.
If you do not do that, you will end up with a generic fantasy world, with no dynamics, where an "infantryman" or "longbowman" is just another name for a combat entity template.
in my opinion, this is the biggest threat to elementals succes. Don't forget that fantasy environments need to support game- emergent culture and history, to really make the settting work on a higher level.