Email inboxing is relying more and more on both the domain reputation and the IP reputation. Some ISPs rely more on the IP reputation, while others rely more on the domain, they are shifting more to the domain though, because it is harder to change the domain due to all the data that needs to be moved. Generally there is an underlying issue that should needs to be resolved before making a change. First look at your complaints and why you are getting them, look at the list quality, evaluate your content, look at your IP reputation, and check your domain reputation. If none of these seem to be the problem, then at a last resort setting up a new domain might be the right thing to do.
