The Syllianon map cannot be fixed by making streets wider for captain's mode imho. With the unit's AI and generally how the game plays, it is not compatible with the streets and a few townsquares. If anything, it could serve as a TDM/skirmish map, but for captain, it makes the outcome too certain. Like Battania and Khuzait have almost zero chance of winning if both teams know what they're doing. Or the strategies to win are so narrow that they take long research and many tries to do them right.
And I also somewhat agree with Battania being quite weak lately. However, I cannot say the exact reason here, whether it is unit stats or unit counts.