I've heard bits and pieces of it from everywhere and think that this idea is too big for the general Fanfic Idea Thread so I thought we could use this thread as a little think tank for such thoughts.
First off, I heard there was a planned route that even included things like a grown up Illya. I would like to gather all the information about that here in this convenient to access thread.
We could talk about power balance, possible alliances and possible antagonists and so such that would go through the ideas of route planning.
Possibly discuss fics that tried it, their shortfallings and improvements.
Overall a good discussion on Shirou's routeless little (really older) adoptive sister.
Note: Mods if you deem this unworthy of it's own thread then we can just move the discussion to the normal ideas thread and you may proceed to lock thread.