10000 concurrent players?
moveable physic objects eg. Crates you can push.
A large 1000 km2 map of a city with 80% of the buildings having interiors?
(Can't see this being possible without occlusion culling)
Fps combat with 3 hit boxes on each character.
The objective is to keep the map large enough that the player base would be spread out.

Just wondering that kind of hurdles might be face with this.
Thanks.

I think the concurrent players depends of you.
But the engine can make huge worlds:
http://www.youtube.com/watch?v=CFgBlfp01kE

Interiors, as I know, isnt rendered if you are outside or isnt seeing the inside. So it wont be a problem too.

The physics can be handled inside the client, but if you want to handle everything on server, you can have problems. But isnt a problem for Esenthel, i think. Its a machine problem! hehe

As I study Esenthel, I still didnt found anything that it cant handle. It is just an SDK, you need to do almost everything.

Cya

"10000 concurrent players?"

The real question is: can you program a server which can handle 10000 concurrent players?