The idea to bring class system, pair up, supports and other Fire Emblem mechanics may have been born out of good intentions, but the result is abhorrent.
The character roster, which wasn't too large to begin with, shrinks down even more once you realize that every pegasus knight plays the same, every bow user plays the same, so does every myrmidon...and so on. With such low variety in character playstyles, the already monotonous musou gameplay becomes boring really fast.
You should forget this game exists. After all, even Intelligent Systems already did.