I have to congratulate the Devs that they have already reached a good balancing - in my view. I can not see that the Brotherhood is op. Its certainly in the hand of the team-play to gain victory or not. I had games were GDI rapped the NOD base with tanks in minutes after the start or were mammoths were all over the place and GDI airstrikes annihilated whole armies in seconds. Only with team-play, coordination and tactics the brotherhood were able to crush this massive power On the other side NOD stealth units were destroying a complete base nearly unnoticed by a team of 20 GDI players. (I have played six hours straight)
Certainly there have to be a lot of fine-tuning for every unit, otherwise the game becomes too hard for fresh players and the fun is shrinking for the veterans. Also the role of the playable characters and vehicles and also countermeasures must be easier to find (I didn't knew that die GDI APC can detect stealth units until I found this information here somewhere in the forum^^)