Aside from the fact that these armies seem to be incredibly annoying and spawn way too frequently (4 armies fighting light hexes at the same time at the time of this writing), they also seem to be too powerful.
In the patch notes it was noted that "They are not as powerful as the Capital Armies". However, when I checked at 21:25 on April 4th, the Dark Army had just won 2846 CPs on hex 90, and a Dvergar army just won 2858 CPs on hex 135. That seems to contradict the patch notes about the power of the new armies.