Also consider the license fees involved, based on your question I get the impression you didn’t do any research on this?
But the obvious, but still my reaction:
BGE,… if you invest the license money you intent to on an engine like unreal,… and put half of this into the BGE development,… you will be able to tackle any problem you encounter with the BGE.
And as indie developer you are aware of the requirement of being able to code/program within your development team,…
and what is easier to dive into then the BGE? Especially seen your experience and above all the Open Source nature of this solution.
I bet asking this on the unreal engine and unity3d engine or the cryEngine fora, and you will get similar answers: they prefer their engine.
I have some, though limited experience and did my research towards other engines and hence my presence here: I have chosen for the BGE.
So my advice is BGE for the win!!
If you can’t achieve what you look for with the Open Source BGE, then changes are you aren’t able to to achieve any better with those other engines. And if you take into account the money involved you are better of with the BGE.
And for any starting indie company… I expect most of them would choose the freedom and ease of use of the BGE.
Hardly problems you can’t tackle, and as a (small) indie, you do understand and know to value to community aspect of the BGE.
If you knwo you do not go for BGE, then I would recommend to use Ogre.
Would… yes would, because based on the information provided, you encounter problems with the BEG because you feel like you are limited by the BGE’s current capacity and your needs simply can’ t be matched.
But with Ogre, where you even have more freedom, you will need to develop it completely yourself.
Which brings me back to BGE,… most of it is done you just need to fill in those small specialized gaps, which no one was able to fill yet (either because they do not need them, don’t care or lack time or money to do so).
When you encounter a problem with BGE, you solve this by creating the solution,…
but the same counts for the Unreal- and cryEngines out there.
So if you encounter a limitation you can’ t overcome with BGE, it is likely that it is a problem you can’ t overcome at all.
And then again, you are best of with BGE,… because if there a chance to overcome this problem and provide a solution, then BGE community is probably the first place to try to achieve and solve these problems / hard limits.
So you need money or others who can solve problems for you, also involving money (or other compensation),…
and BGE is probably the only engine which lays within your reach (based on the information you provided).
I hope this helps you to make up your mind and can start to either lower your goals, find solution to work around them or solve them completely.
And since this is all possible with the BGE, I sincerely hope you do understand this, before wasting time and/or money elsewhere then to either give up or come back to start where you left.