There’s plenty of epic, sprawling fantasies in the Choice of Games and Hosted library. Choice of Rebels, the Lost Heir trilogy, the Evertree Saga, The Aegis Saga, and The Soul Stone War to name some. If the question is about whether or not such a story would fit, I don’t think you need to worry. I’m sure your game would be an excellent addition.
However, if this is a worry about scale, based on observation, sheer workload for you could be quite the task specifically in writing all the branching and accounting for how creation can balloon far out of control with these games in general, let alone admittedly massive WiPs. Only you can decide if it’s worth it to you to forge ahead anyways. If there’s any doubts in your mind, I would urge you to do a ton of research regarding what goes into these projects, play as many as you can, really ask yourself if you want to write long, interactive fiction or if you’re looking to create a simpler, non-compromisable tale.
Also, side-note: I moved this discussion to game development - writing & content because the general category is more for when nothing else is suitable and this post basically asks about writing advice.