Firefly doesn't need to be rebooted. It was fine the first time around, and it was envisioned just right. What it needs is not a reboot, it needs a revival/continuance.
Babylon 5 ... the nature of the production "network" messed up the second half of season 4, and ruined season 5 (IMO). Further, the sequel series was ruined by various other issues (chiefly the network airing it). It would be interesting to see how JMS would re-do the whole thing if he had the chance.
Highlander ... there are like 2 or 3 different attempts at a back story, several disconnected movies, 2 different tv series, movies that are based on the series and not the original movie(s) .... it's a huge mess. I'd be nice to see a story that has a central arc (like B5, where it's known up front and told in a slowly revealed and sophisticated manner... not like BSG, where they made up "the arc"/"the plan" as they went along, and just barely pulled it off), but more importantly, it has a definite continuity that the existing mess lacks.
Space:1999 ... obviously, they have to change the title. But it was one of my early favorite shows. I'd love to see what a talented writer could do with it. Again, I'd want it to be an arc story, that is pre-envisioned, and not made up as they go along.
The article referenced brings up Buck Rogers. If they could do it more like the original 1930's, and not like the 1980's, then go for it.
Dune was already re-done, on the sci-fi/syfy channel ... like Firefly, it doesn't need a reboot right now, it needs a continuance (the rest of the books).
One other idea: The Six Million Dollar Man. Only, NOT done by the people who did the reboot of "The Bionic Woman". That was AWFUL.
What about that old kids show: Arc 2? With the vehicle that drives around a post-apocalyptic planet trying to find a way to re-build civilization? That might do well right now.
Or the Shazam/Captain Marvel show of the same era. With or without Isis.
Oh... and... what about Mad Max/Road Warrior? I think Mel is too old to pull off a sequel at this point, so why not a fresh look at it.
Someone mentioned Aliens ... maybe. Or even a complete revamp of the Terminator story (and, again, done with forethought, and not "what can we shove into the sequel this time, and pull out of our butts to sort of make it work?").