Well, gunpowder was invented several times in different places in different forms... I'm no expert on the subject though so whether there was any sharing of information between the various inventors (directly or indirectly), I don't know.
But anyways, yeah assuming perfect sharing of information, things tend to only be invented once because you can't invent something that's already been invented (that's called copying). Without good information sharing, things are/have been invented multiple times all the time.
But I'm with you anyway - I don't want gunpowder and stuff in this game. I wouldn't mind seeing things like airships, and other mildly steam-punky contraptions, but mostly under the condition that what keeps them afloat, so to speak, is magic, rather than technology.
A mini-expansion or content package that introduces steampunk-ness into the game would be fine with me, though.