These may have been suggested before, but I'm throwing them out there.
1. Do not hide deployments/reinforcements in the game log of a fog of war game if they happen on visible territories. Let's say you're playing FoW on World 2.1, someone drops 20 on Angola, which you border. The log should say that, instead of saying 20 on ?.
The same goes for reinforcements, though if the player reinforces from a non-visible territory to a visible one, like say from Western US to Southern US, the log might say "reinforced Southern US with 20 troops from ?"
This will allow you to keep track of enemy positions with more ease should you lose your position in that area. It helps the player get a better idea of how the game is progressing without removing anything from the concept of fog of war.
Resignation function. I'm sure this has been discussed before, and I am fairly certain this doesn't already exist only as an incentive for people to go premium. But being caught in an intractable, but surely and VERY slowly losing game is annoying, to say the least. Allow people to give up on their turn. In games with more than 2 players left, the resigning player's territories would become neutral; in team games, they could be divided amongst the rest of the team evenly.