The Sharmas could have worked at one point, had Trudie Goodwin agreed to come on board full-time as Georgia. Georgia, Rishi, Jai, Charity, Noah, Nikhil, Gennie & baby plus Priya under one roof would have provided multiple storyline opportunities. But I think they've missed the boat on this one, with Nikhil and Gennie now gone, Georgia and Rishi seperated, not to mention the horrible Archie storyline.
The original concept for the Maceys as created by Gavin Blyth wasn't bad - a fun family who would bring some life and a bit of comedy to Home Farm. Unfortunately Blyth died shortly after their introduction and they were left in the hands of Mr Blackburn, who didn't have a clue what to do with them.
I would say a new family with happy characters and settle them in with a bit of comedy before throwing the angst at them. The Tates, Kings and Wyldes were fantastic but maybe it's time to bring something new to the Home Farm table. Megan never filled the shoes of Kim Tate, Sadie King, Natasha Wylde, etc. because they never really explained her bitchiness.
Another idea would be to bring Kathy Tate/Glover back with her new husband, child and mother Mrs Bates, and move them in on the pretense that the husband was wealthy. Kathy would make a good, firm but fair style of lady of the manor, respected by the villagers, with good knowledge of both the farming and horse-riding sides of the business. And with links to both the Sugdens and Tates, the perfect host should they decide to reintroduce any off-canvas relatives, such as Joseph and Jean Tate or Robert Sugden.