Orzo doesn't replace rice, it complements it. I first learned how to use it from a Lebanese friend who browns the orzo in olive oil then adds the rice to heat it up a bit then adds the liquid. You have the classic browned pasta amongst the rice (I use Basmati most of the time now). Those in the US (at least) think "Rice-a-roni the San Francisco treat" for a similar boxed approach to this.

Cook orzo and rice with chicken broth and it's almost a whole meal like that. In winter I make that mix (adding the browned pasta and rice to my rice cooker) with lightly sauteed chicken breast and sliced mushrooms and it comes out a perfect comfort food.

Today I have the carcass of last week's chicken simmering to make a rich broth. I'll freeze some of it and use the rest this week.