It helps that most of your party is on horseback.
Seriously. If everyone was just walking around on foot like losers, it'd take fooooreveeer. Are there mounted offensive mages?
Random question! Are there any FE games where you don't fight monsters? 'cause in Sacred Stones my interest dropped significantly once they rolled out the monsters. No more weapon pyramid, no more politics, just "Go kill the evil dudes cause they're evil".