You're actually not restricted to the restaurants in the hotels. There is a mini mall called Bali Collection with a handful of restaurants to dine in. Most resorts will provide transport to the mall.

Also some restaurants around Nusa Dua area will provide free pick up/return service when you make a booking with them. Bumbu Bali comes to mind. There are also small restaurants on the periphery of the gates of the area. They provide free transport as well. I've never dined at the hotels' restaurants except for breakfasts and we we're
fine. And yes Nusa Dua is a bit dull and far from the tourist sites.

The private villas at Sofitel are quite pricey. Novotel Benoa is not ancient at all and is a good value for their private villas with private pools. Mgallery Amaterra though very nice, is not by the beach.