got my hands on a friends copy of the original, and immedietly gave it the full Native Expansion v0.585.
Game is a HELL of a lot more fun than vanilla Warband. The one siege battle i fought defending in warband was great but was really just everyone standing at the apex of a ramp and slicing all enemies at the top. I'm guessing campaign ai is more or less the same in all other aspects. Between the merc warbands, Khan warparties, deserters, the native world is much more exciting. Can't just click a location and go afk till I get there.
The hack and slash of battles seems more awkward in Native Expansion v0.585 than warband but could be my switching over to a 2h.
Found this link listing compatable mods to Native. Are these mods compatable .585?
http://forums.taleworlds.com/index.php/topic,44196.0.html?PHPSESSID=1f865a2b663c4d1c657c0e1bbece760c
ps the increase in available missions is awesome too.