I think this is my favorite idea I've seen in this thread so far. There are a ton of great sci-fi novel series that have never been adapted, and if we throw comics in there too then we have even more.I wouldn't -- B5 is done and a reboot would just be more of the same. Perhaps reboot Crusade. Preferably, I'd adapt a literary SF universe such as Banks' Culture, Reynold's Revelation Space, Niven's Known Space, Simmons' Hyperion Cantos, Hamilton's Commonwealth or Confederation, or Baxter's XeeLee, Manifold, or NASA series in descending order of preference. Lots more possibilities than these, of course...
Honestly, they tried three times so far to continue the franchise and each one failed, and now they can't even drum up enough interest for a Blu-Ray release. I don't think there's really enough interest out there at this point for the franchise to continue in any form, so rather than wasting time on a guaranteed failure, it would be better to look for something new that might actually succeed.