My issue with gunpowder is that it's a technology that transcends cultures. Basing a faction entirely on a technology is bonkers - it would be like giving exclusive access to crossbows to Rhodoks. Rhodoks are the best crossbowmen, but it certainly doesn't mean Swadians can't run around with crossbows. It doesn't make any sense that a technology that effective wouldn't seep out to the rest of the world, especially given how small Calradia is. If one faction has gunpowder, all of the factions would have gunpowder, and that doesn't fit the vibe they've built in Mount&Blade at all.