I'd have to see the specifics, but unless you're really desperate I would have given them combat promotions. Crossbows are more often used as attackers than defenders, and when defending it's generally against units that they would likely win against anyway.
Civilization IV: 21 (Bismarck of Mali), 29 (Mao Zedong of Babylon), 38 (Isabella of China), 45 (Victoria of Sumeria), PB12 (Darius of Sumeria), 56 (Hammurabi of Sumeria), PB16 (Bismarck of Mali), 78 (Augustus of Byzantium), PB56 (Willem of China)
Hearthstone: ArenaDrafts Profile No longer playing Hearthstone.
Hearthstone: ArenaDrafts Profile No longer playing Hearthstone.