To me it already seems like Bannerlord is more complete than Warband.
For warband the base game is very bare bones. I find myself referring to "vanilla" in my head when I was actually going back and playing a Mod (Floris Evolved, technically a collection of several mods) and only considering it
as vanilla because it was the most basic mod I played, still using the base map, factions, etc.
I have only played the
actual base game Warband once after having started down the Mod path... and it is so basic that I will probably never do it again. This is the main reason I keep putting off using Mods in Bannerlord... I know that once I start... there is no going back
Now if you are referring to complete "with mods," then yeah, that could take 10+ years.
I recall one of my favorite Warband mods, Novas Aetas, not working properly because I had a newer version of Warband that the mod had not been updated for. It is always a shame when mods stop being supported. I am very strongly tempted to wait until Bannerlord stops being updated before I start playing around with mods
Novas Aetas, by the way, had an incredibly fun colony building minigame using TaleWorld's in-game map builder (normally not accessible
while you play a campaign). There were also social classes, religions, crusades, peasant mini-games (mining, farming, hunting, etc.). Also, you could also build a limited number of castles
anywhere on the map, no need to conquer others to start your own kingdom. So many more roleplay possibilities galore. It blew my mind
.