I think it is a no-brainer to include this for champions. Also dual wielding. I don't know why but people get crazy excited about dual-wielding.
But what about troops? As it is right now, why bother. Just continue to use your bow from point blank range and avoid the cost of an extra weapon and the risk of counter strikes.
HOWEVER, I think that secondary weapons for normal troops would a great addition as part of the general combat overhauling they are planning. If changes to damage types, ammo for ranged weapons, attacks of oppotunity for breaking engagment etc get into the game, THEN the expense in terms of ingame costs and the programming effort to make weapon switchs possible would be worth it.