Wow! Amazing progress here guys. A bit too short on time to fully catch up with all the detail but it looks like Blue is taking up the reins admirably. Top work sir!
Thoughts on map:
The map is looking great and I fully agree that the Mughals map was too small to have done the job for this scenario. I was going to suggest the rotated approach to get more north western in actually. It's a prefectly good solution and the common sense way to go.
I haven't had time to look through the recent posts in detail but I think option "B" above looks the best.
"A" has way too much going on north of the Himalayas (though I mention some possible benefit that could be derived from this below) and the scaling required to get that extra land in does a disservice to the mainland where all the main action should be. "C" isn't too bad but probably has too little land around and east of the Ganges delta imo. You probably need just a lil bit more than what's there in "C".
So, on a first view, I'd vote for "B". It seems to provide all that's need and not too much excess. The scale is good, the right amount of action west and east and north.
I don't think one needs to get too hung up on the curve of the Brahmaputra river. As long as you've got some space in the delta area for a backward civ that's fine. And that civ, whether Nagas or whoever, is just there to provide
something for the Mauryans to keep in check rather than have a completely clean backside, so to speak. They should be something like the Burma civ in Mughals I reckon.
Terrains:
My two paisa worth also says that desert is going to be a very key terrain in this scenario, given the map options offered. (Jungle too of course.) I would suggest to create some mechanism with desert and mountain terrain to stop or drastically hinder those civs south of the Himalaya from going there, to prevent distraction for them. That can be done with terrain movement cost / wheeled units on both desert and mountain terrain. Maybe even disease from such terrain, though I've never played with that function so wouldn't be confident how to exploit that.
There's a lot of mountainous desert up there begging for say just Buddhist monks being able to run treasure/relics around there. Those lands are also of interest to Saddhus too.
You could exploit the same technique with the same sorts of terrain to create a difficult situation for central civs with the likes of the Bactrians and the other marauders in the west. This would give them 'terrain homeland advantage' like with the Himalayans and make western campaigns for Sikander and the central Indians more of a challenge.
Also:
I, for one, would feel like I hadn't been served enough dhaal and rice if there weren't many different elephant units in the game. Like, much more than two. Four, different ones at the very least, I'd say. I had two different ones in the Mughals scenario and that's only because there were just two such units worth including back then. And that was years ago now. There are so many more to choose from now, so let's go to town, pretty please. Happy to help out further with unit suggests when the time comes. And I loooove the idea of an elephant worker. That is brilliant!
Blue Monkey said:
Three guesses who Sandrokottos is.
That's Chandragupta! But I have to confess to not knowing Poros' real name.
Maybe place another small group in the spice islands? Trade followed by conquest would match the historic pattern. Even got 
