First off, the only way I would wan't to see any of these franchises adapted for film is if someone from the game company (who is still passionate about said franchise) gets to veto any and all of Hollywood's bullshit they pull with adaptations from any other media. Most video game adaptations were meant to sell tickets on brand recognition alone. They just don't get any heart and soul put into them.
Star Fox might work as a film. Although, it would be hard to get more than the fanbase in theaters. I bet the average moviegoer will write off a movie about anthropomorphic starfigher pilots as kids' stuff. Let's stick with a TV show or direct to DVD/stream film for now.
Mega man is one of the more mythos-rich franchises here. I would love to see at least a successful (and more serious than the Rubie-Spears show) TV series that later gets a sequel series that follows the X games, and maybe beyond. Capcom just needs to get out of their "if it ain't Street Fighter or Resident Evil, it shouldn't get much attention" mindset.
The perfect Contra movie set sail to "not happenin' land" when Ahnold Schwarzenegger and Sly Stallone aged. A decent Contra movie flew out the window when Konami gave up giving a fuck. (At least a fan film might happen someday.)
Kirby? It might have the highest of the list, but chances are good they'd aim his movie at the super young crowd, despite the hidden dark tones of the series.
Maniac Mansion is too obscure. I forget it exists. A studio would buy the rights only when they really felt desperate for a base for a script, not something they buy with hopes to drawn in people from brand recognition (like most game movies). Then the numerous rewrites would churn out a script unlike anything from the game.
Screw Kirby. Starcraft has the best chance, especially
if when the Warcraft movie makes its budget back in the first hour. I also predict it to top South Korean film charts for a long time.
Zelda isn't happening, not by a long shot (pun intended). Nintendo doesn't want Link to talk. Many fans don't want Link to talk. (I'm of the "he speaks, but the player doesn't see the dialog" variety.) Plus, its Ninty's second (non-Pokemon) top tier franchise. Some of the older leadership are probably still feeling the sting of the Mario Bros. movie. (Of course, if by some miracle a good Zelda movie was made, I'd break my personal boycott of cinemas to see it.)
Elder Scrolls is another one I fear Hollywood would dumb down to the point of it being seen as a Tolkien ripoff. The games already draw a lot of inspiration from Lord of the Rings. The rewrites will likely remove most of what sets it apart from other Tolkien-esque media. Being a non-interactive film itself would remove the other aspect that sets it apart: it's your story (read that in Tidus's voice for extra fun).
Speaking of FF, Honestly, I'd rather see a Final Fantasy turn into a film. FFIX is my top choice, since it's a mostly unique fantasy tale that has elements of the previous games in there as well Second vote to FFXII, since it's the next best fit for world wide audiences, IMHO. If only Square Pictures made something like that instead of that weird (albeit decent) movie about ghost aliens set on Earth (as in not a fantasy world the franchise is know for). Although, I wouldn't want today's Squeenix to even think about branching out into film.