Well, to be honest: If you target core gamers, you should use a proven AAA engine like cryengine, unreal or source.
Just because they are optimized for one genre.
Oh, and you should at least have a big pipeline with a lot of good and succesful projects, otherwise you won´t get the needed money.

If you got a budget of >5.000.000 usd, then you won´t fiddle around with indie authoring systems.