There is a "cap" on the morale formula at -39 for the distance to capital line, and you can approach that limit without going all the way around the world, so that does help.
I have never been happy with moving my capital. It seems to make things worse.
My keys to a good morale on the 100 player map include keeping a couple of peaceful small/medium sized AI countries locked in the middle of my country, fairly near to my core, and using them to "capital farm" at a critical point. If you can pull off capturing an enemy capital one day, and ALSO capture two of your "banked" AI capitals on the same day that will get you +30 to all provinces morale, and that will keep you going for a week or so unless your morale is really awful due to an extra shortage of food and oil both.
Another thing I like to do is keep to my own continent until I am ready to break out. I can maintain my own continent, build up food, oil, army reserves, research the units I want, and be ready to take the rest of the world by storm when the time comes. Of course there are times that I have to act early due to the timetable of the enemy.
After you play a few 100 player world games you will find your groove.
I will say that starting with a couple of friends and planning on a coalition win has made morale and food management much easier.
I assume you have read my >> Complete guide to morale and rebellions.
