> "I think it just breaks way more stuff than it solves. The new model ends up being a worse fit for pretty much everything else but the galaxy rotation thing."

This is often mentioned as a reason not to spend time with alternative models. However, breaking stuff is sometimes necessary if we are to get out of the local maximum of theory usefulness. The Kopernik model was much worse fit for the observations of planet motion that the Ptolemy's model, but it did have other virtues, like simplicity. The broken parts got fixed later with development of mechanics and perturbation theory.