I'm looking forwards to this. Empire/Napolean were pretty fun but got old due to the lack of variety in units and no castles to seige. (in addition to all the other problems those games had, especially before bug patches).
I think the medieval-period settings have always been more popular due to the variety of units and tactics available. I never got to play the first Shogun, but I assume its similar to the Medieval games.
I'll try to download the demo but my best download speeds are between 40-60kps and suck up all my bandwidth so I can't even surf the net or check e-mail. Steam is usually extra bad and has a tendency to just randomly crap out for no reason, requiring me to baby-sit Valves shitty program.