Well I don't think OTTD is very complex in native ;p Complexity is only added by mods(grf's) and unofficial (code) patches.
If you make a SIM, then I hope you do make it MORE complex than OTTD is in native
But complexity doesn't need to be upfront. As long as the simulation is deep enough behind the scenes, it can all be abstracted. And maybe it should.
You know.. The new sim city is bashed for good reasons but every time I play that I wish there was an TTD with that engine. 100% Agent based. Fully modeled production cycle - > 1 "agent" ore + 1"agent" coal = 1 metal agent. These agents sit in depot until they are loaded on trains, each cargo train car has a different setups for how agents are packed together, so 1 car loads maybe 8 agents as a pack. And they are unloaded as pack. Packing is a process that takes time and isn't instant, and switching between car and train requires identical load configurations. Or a repackaging method.....
It's just sad that Maxis/EA is not gonna do that. No money in it.
Thing is, the way Sim City 5 works right now, it would work far better as a TTD game than a Sim City game. How weird is that.
by the way, my current favorite patch pack is a russian one
http://www.tt-forums.net/viewtopic.php?f=33&t=66892####
I am intrigued by a sim game from Arcengames.. and when it is a space management sim game? all the more. After all, you guys make games that no one made before you
And that's good. Even if not everything is for me, at least it's all unique!