Hello, I just tried that map in single player. Not bad for a first try. However I think you should try to shorten the wheel distance between bases to about 100 seconds (you are now at about 200 seconds). here is some reasons why it's important.
1-
Unit production : imagine that one player is ahead, we WON his army is much bigger then the enemy units, so he launch the final attack but it takes over 3 minutes to reach the enemy base and by that time he have an extra full army ready to defend
2-
Research upgrade : Same goes for research, we have a new component every 5 minutes or so, by the time you build a big army and more then to the other side, it's already obsolete. It push the players to hide in the base and focus on research forever.
3-
Propulsion imbalance : To compensate the long distance time, players will tend to use wheels or hovers more. But some weapon are stronger against some propulsion, or stronger with some. Rockets for exemple are bad against hovers. On a more competitive level, it's possible your map degenerate into flamers vs flamers in every single game.
4-
Ignorance of impending doom : it may take 20 minutes for the player in one corner to learn about the quick death of another player on the map. Someone may have a 25% power advantage, you may play another 15 minutes unaware of it, but once you realize it's too late and it's a steam roll.
It's possible that you try to make longer games on purpose, but it's not the good way to do this. Because the winning player doesnt really have more challenge or more chance to fail, he's will just make the losing side suffer a slow death over 20 extra minutes.