Here's a nice idea for a reboot. How about telling the story from the point of view of general Hague (later major Ryan). Get a pilot for his/their role(s) during the Minbari war, and if it catches on start the series roughly at the same time B5 started. Both B5 and "Hague" running on parallel timelines.
Only disadvantage I can see is that the final result will already be known for fans, but the voyage should be more interesting then the destination. Another big risk is messing with existing timelines, in particular if/when the studio starts giving "helpful" advice.
One other thing. People keep mentioning reboot as if to say start again from the beginning. Now English is not my first language, but does reboot not literally mean a restart? As opposed to starting over? So a reboot could start at any time within the known (or unknown) B5 timeline. So it need not necessarily cover the period B5 already covered.
Anyway, just my two cents. Everyone best wishes for 2014.