I love both of the Fable Games, but I happened to like the second one a bit less than the first. Fable 2 removed some items that I really enjoyed, including the Chain and Plate Armor look. Not to mention how we were able to sneak into homes and stores and steal items that were on the shelf. Seriously, what happened to Sneaking around from the first one. If you listen to Yahtzee (Of Course You do) then you hear one of the concepts is that picking sword combat is the one mostly used by enimies so he is forced to take the same decision as well.
Part of the problem may be solved if they brought back the Physical Shield Spell from the first game, bring back the sneaking around, keep the possibility of owning metal armor again, and add veriety to the diolouge to possible significant others. I was mostly fond of the Balverines from the first Fable, which make them look like werewolves than just mutated monsters. And one thing that was really tedious in Fable 2 was how you drink or eat, having to open up the menu every single time.
Thats all I can think of for bringing back game content from the previous Fable, but now I would like to voice my Opinions on how to make the game better by adding something completly new. The ability to kill your kids would be nice as Yahtzee suggested. Let your children grow up without the need for it to be done after the quest (Like after saving Garth) and increasing the age in which they could be adults and move out of the house. Thats all I could think of at the moment but I still am kicking around another idea or two.