So somethings are going to be hard to tranlate from one thing to another when it comes to adaptations. Some easier than others.
So which ones would need alot of overhall to work? A good excample o one that did is would be the Roughnecks Cartoon which took the best elements of the Book and Film of Starship Troopers and left the rest.
In particular, I think the works of HP Lovecraft would need some triage before they got adapted. Hear me out because the main thing about him is he did put alot of himself into his stories, and unfortunatly that meant alot of classissm and racismn, and other forms of prejidices that would make a Confederate Flag Waving southern Steryotype tell him to turn it down a notch.
Not saying it couldn't be done, everyone from the Ghost Buster Cartoon from the 80's to Del Toro have taken elements from it, but it would need work. Also, how would you make penguine's scary?
I imagine most animated stuff cartoons or movies would be very challenging to make into live action effects. The real advantage of animation is that whether you're drawing people walking in a garden or flying through space with crazy laser [powers, it basically costs the same. So the instant you start taking advantage of that fact, you sort of lock off any kind of live action option without significant effort. The whole idea of a live action Avatar has me worried for that very reason - in the cartoon it was made very clear that what can be done by expert benders is very visually impressive, and without dumping money hand over fist into CG that won't come across the same way in a live action setting. Unless they do the Sky Captain and the World of Tomorrow thing and do the whole film in front of green screen.
HP has his own challenges just in terms of the topics of the stories. We can get rid of some of the unpleasant parts of Reanimator so we describe the boxer with less WOW OFFENSIVE terms, but it will be a hell of a re-write before the Shadow Over Innsmouth becomes not about interracial marriage and why people will turn into fish demons because of it.
Bioshock 1 could only ever be a video game.
For the longest time I thought Ender's Game was impossible to translate to a movie. Too much time spent talking about politics and what is going on in Ender's head. And it is spread out over so many years (due to the time dilation)
And yet the movie was actually decent!
Minesweeper will only ever be a video game!!!...
...or will it???
Wait a minute, whaaaaaat, there is a minesweeper movie!
I think another one would be to do a Tenchimuyo series in something other than as by Japan for Japan in liveaction. As Much as I enjoyed that and Tenchi In space, you would need to do some overhaul as its very Japanese in how charectes dress (even the aliens), or the designs of some of the items like the two robots. The mask Roroki has is slightly Kabuki looking. Also, outside of say some of the dating reality tv shows like Flava of Love or the Bachlorette, harem shows are not really something that is popular i don't think outside of Japan.
Speaking of needs some work: Love Hina. Holy crap, and I sought the relationship between Edward and Bella could hit every checklist on the domestic abuse warning signs.