it's natural that they'd focus on them - Tomic's run in Wimbledon and Sam's 2011 preformance do warrant attention - Swiss TV focuses Roger/British on Andy - French on Tsonga / Monfils...etc
Exactly. It's nothing new for countries to focus much more on their own players in tournaments than players from other countries, whether it's right or not.
As for the debate as to whether Tomic and Stosur are worth attention, I would say they definitely are.
Stosur has won a slam, beating Serena Williams in the final. She's earned the spotlight. I don't think she'll win the AO, but good luck to her in her quest to do so.
Tomic, while I'm not overly keen on him, has a great game, shows a fair amount of court craft and has delivered performances which warrant excitement from anyone who follows him. He could well have a big future in the game. I'm a Hewitt fan, but I think they're right to be focusing on Tomic at the moment. It's uncertain if Hewitt can win matches on the big stage again, and here you have a kid who was hyped up for years and is now climbing the rankings fast. It's totally logical to give him the spotlight, even though it could put a fair bit of pressure on his shoulders.