Muskets are very slow and innacurate. Most of the fighting will still come down to melee combat. Comparing this to any other run and gun FPS is pretty laughable to be honest. If you haven't even played the game, why stretch so much just to prejudge it?
This is not the same game that was released in Poland in 2009, much like Warband isn't exactly the same as the original M&B, even though it shares the same campaign. F&S will have higher detailed models, textures, battle formations, new campaign elements plus a new multiplayer mode allowing players to direct their own AI squads. Advertised as being 16 players, 24 AI each. So that's 384 men on the field during multiplayer! Show me, where else I can find that...
Now this doesn't mean it's time to abandon Warband. Warband is a different period and awesome in its own right. But to deny that this new product will bring anything new and exciting to the franchise sounds more like cognitive dissonance to me from people who have already prejudged it on the basis that they don't feel like making a new purchase.