it's certainly not a bad food at all.
in my personal opinion it ranks higher than wellness for example.
as for variety - it's certainly a good thing,
if the dog tolerates it. but in some cases the condition and wellbeing of the individual dog dictate what you can and can't feed. if the food is of good quality, and even better if you can offer some fresh foods for variety, there is nothing to worry about.
i know of highly sensitive dogs who for years have been on a home prepared diet that consists of only a small number of ingredients, simply because they can't tolerate anything else and their condition can only be stabilized by leaving out whatever causes problems. if that means that a dog would have to live for example on ground turkey and sweet potatoes for the rest of his life to be comfortable, it's all you can do. sure, you'd want to look for a nice multivitamin/mineral supplement the dog can tolerate so no deficiencies occur, but the dog's health is not going to suffer from lack of variety.
even on a raw diet you can achieve variety without feeding many different meat types. te key on variety in this case is that you would basically offer all the different parts of a prey animal (e.g. not just plain muscle meat, but also heart, liver, lung, spleen, trachea, intestines maybe even with their contents, the head, tail, etc.). if you look at what nature offers for example a wolf (not a comparison i like to make, because it's incorrect in so many ways), you will find that deending on where the wolf lives, he might be very specialized on a particular type of prey, depending what animals live in the area. for one that might be predominantly elk, for another rabbits, and so on.