It's one of those really interesting and ambitious synthesis games that went out of fashion for a while once the standard genres, formats and designs were worked out. There were quite a few oddities in the 80s and 90s that would be hard to place in a single category. A lot of experimenting and risk taking. The manuals and the obvious love and effort delving into the settings really made them for me.
I really enjoy the path from a low level leader with maybe a dozen men right up to ten thousand or more and half a country under your control. Higher risks and rewards as you go. The changes to mechanics and abilities was a very nice touch too, allowing you to send your underlings to deal with threats just as your lords in the past requested you and others to help him. The combination of strategy, tactical battles, action, combat, dueling and the solo stealth run or gauntlet style slash through bandits, assassination of tax collectors, rescues and kidnaps and the clear desire for a role playing and historical feel to it with a touch of the culture to come through is hard to find to say the least.
The closest I can think of too would be the bigger mods for Mount and Blade that flesh it out to this kind of level. Total War is just too far removed from this game to count for me. No personal combat. The RP element and immersion in that is greatly reduced. All the solo missions and dueling are not there, replaced by the clunky agent system. The rising up the ranks and the changing of the game and maps to match that isn't there either (you're a faction, you grow and that's that - like the end stage of this game only). Maybe TW:Shogun 1 would be closest in some ways, like a sequel or spin off could have become a true successor...but not to be.
Some other games of the era and Microprose games had kind of similar feel to them with random events, RP and commanding others. One obscure game that comes to mind that you might enjoy is Legion by Gobisoft. It's free IIRC and can be found online for Amiga or Windows. More emphasis on traditional party based RPG so weighted in a different direction but still has conquests and a feel of expansion from a small beginning as you make new additional parties.
