My answer would be yes....
In the bigger scheme of things, do you really think that keeping a tang in a 55 gallon vs. a 180 gallon tank makes a significant difference when compared to the ocean? I wouldn't think so. I started out with a 55 regular and kept a yellow tang and a blue hippo. I eventually updated to a 220 within a year though. Probably wouldn't be a great idea to keep any medium size or full-grown adult tangs in a 55, specially since some of em grow in upwards of 12". Tangs are known to be a very sensitive fish, prone to some stress related diseases. Having a bigger tank with any fish gives it more room to "open-up" and relieve some of that stress. You will notice that tangs especially are constant swimmers that like to roam the environment they're kept in.