With Fable now owned by Playground Games, the franchise is not dead yet. That being said, Albion is not a nation where technology stands still. From the Middle Ages, to the Victorian Period, Albion has a tireless history. So, it's likely thay in Fable 4, the technology is circa somewhere in the 20th century, maybe even 21st century?
This would mean that by this point, swords, axes and other melee weapons would be replaced by firearms, assault rifles, pistols, grenades, etc. I'm nervous to admit it, knowing hoew controversiol they are in the modern gaming world, but unless they can do a damn good job in a third person perspective, Fable 4 might have to be a first person shooter. Now of course there's still magic, but Elder Scrolls has mastered the art of first person magic.
Another thing that must be considered, should this be the route taken, is the status of the Royal Family. Every hero of fable has been Royalty, one way or another. But the funny thing about Royalty today, is that most of them are figureheads. There are exceptions of course, but do you think that the Albion should still be a monarchy, or should the Royal Family have abdciated in favor of a Parliment and Prime Minister, like modern day England? If so, how much weight does the story put on you, if you're just a figurehead now? Or perhaps maybe this time you're NOT Royalty?