by sporkage
How about rather than percentages added for IB you go with 1 troop per 2 territories controlled, still rounding down and then divide population plus the remainder, if there is an odd number of territories, by 3 rounding down.Let's say you have 3 population this would yield:
territories/normal/IB current/IB proposed:
1/3/3/3
2/3/3/3
3/3/3/3
4/3/3/3
5/3/3/3
6/3/3/4
7/3/4/4
8/3/4/5
9/4/4/5
10/4/5/6
11/4/5/6
12/5/5/7
13/5/6/7
14/5/6/8
15/6/6/8
16/6/7/9
17/6/7/9
18/7/7/10
19/7/8/10
20/7/8/11
So the bigger the land coverage the better the bonus, but you're looking at a troop or two until you start owning most of the board, which should be the goal of IB.