They specifically state these new employees would be an extra shoe in if they had knowledge of 'reimaging' established franchises. Reading between the lines it points heavily toward a new Fable.
The position of Animation Director says an ideal candidate would be someone who has worked on "large scale RPG, Action Adventure and RTS genres." Breadcrumbs!
Lionhead also desire a Core Engine Programmer. The last Fable entry wasn't a traditional one and focused on a spin-off adventure that proved generally uninteresting to the wider Fable community. Hopefully the studio is planning on taking the action adventure RPG back to more of its original Xbox roots.
"Lionhead Studios is seeking a highly skilled and experienced Animation Director to be a key contributor on an unannounced title. The ideal candidate is someone who has leading industry experience on AAA titles, including large scale RPG, Action Adventure and RTS genres."
Experienced Programmer: Core Technology
"Lionhead Studios is seeking a highly skilled and experienced Programmer with specific knowledge of Core game technology, to be a key contributor on an unannounced title."
John Needham, former CEO of Cryptic Studios, is the new boss at Lionhead Studios, leading some to speculate that perhaps they're trying for an MMO. Creative director Gary Carr has teased the developer is "building something more ambitious than ever before" - whatever that means.
If it is a new full Fable in the works then they need some serious overhauling to make it more appealing to the community. Fable 3, for all its improvements over Fable 2, wasn't as big a leap as many hoped for.