I'm working on a major update that will bring some larger map sizes and also a handicapping system.
Handicapping
The handicapping system allows players to start with more or fewer cities than their opponent. Forward Line is a game of skill that requires some practice to master, and it can be very useful to up the challenge against a newer player, so that both players can learn with a challenge appropriate to their relative level. Also, it can extend the usefulness of the AI in single player games by giving it an advantage against the human. It's kinda fun learning to surgically pick apart a continent spanning wall of units coming at you from the AI.
Larger Maps
I will include two new map sizes in addition to the current 24x24 map. There will be a 36x36 map with 18 cities, and also a 48x48 map with 32 cities. You can expect that games on these larger maps will take considerably more time to complete.
I was hesitant to make large maps initially, because I detest grindy games and I wanted to ensure a good balance between game enjoyment and time spent. I would prefer that people spend 10 hours having fun than feeling compelled to spend 50 hours just to feel like they've learned what there is to learn about the game.
After some experiments with larger maps however, I feel like I'm really enjoying certain aspects of a larger map. For one thing, larger continents means that the balance of land combat versus naval combat is more even. Battleships have a very far reach on a small map, but become less important as land masses become bigger. Also, supply networks also become more emphasized as there are more cities and also larger rear areas away from the fighting where it's safer to focus build supply units, rather than the usual situation of fighting for your life at every corner of the small map.
ETA
So far things are mostly in place, however there are some major issues getting the single player AI to handle these large maps. There is an exponential increase with these maps in the number of units that need to receive orders and be evaluated as targets. There are a great many O(N^3) or O(N^4) algorithms the AI uses that are acceptable on the small map, but on the largest map just get way out of hand, to the point of taking many hours for a turn or just crashing the computer if you start with a high handicap.
That means I might have to totally rethink the AI from scratch. I imagine that if I'm not close to finished by February 2019, I may be forced to make the larger maps multiplayer only. Check back around February for further news.