While it is true that there aren't many restaurants within "walking distance" of the Omni (my "walking distance" varies with the heat and humidity), there is a McDonalds at the bottom of the hill, cross the street, to the left which also has two other fast food restaurants in the same little complex. Otherwise, everything is within 6.5 pesos and a maximum 10 minute bus ride up and down the hotel zone. If you want fast food, you've got it - Subway, KFC, McDonalds, etc. If you want Mexican, you've got that - Las Margaritas, Pericos, La Parrilla (to name a few). If you want excellent, romantic, you have that, too - Laguna Grill, Puerto Madera, La Dolce Vita, Lorenzillos. Everything you could want gastronomically is within a 10 minute bus ride. Buses run all the time up and down the boulevard right outside the hotels.
Go, be adventurous and have a blast. The Omni is gorgeous and a great resort. The restaurants in Cancun always make me wonder why people do Al Inclusive.......
Cheryl