That it isn't a series any more so much as a label they throw on games to move copies? Honnestly the lack of clear direction makes it really hard to know how I feel about the series nowadays. At least if they picked one path and it sucked I could just write the series off.
Objection! The sword arts and technology in Japan were no more developed than in other comparatively developed civilizations. This is a myth perpetuated by a combination of anime and Victorian era European historians looking to characterize medieval Europe as unrefined in comparison to modern practice. Furthermore the Japanese maintained an active military use of the sword as a weapon of nobility, thus maintaining a much more active lineage to modern times than European or Chinese styles ....
(Sorry, can't help myself. For more information visit your local library.)