But I'm no legal expert, and I'm confused what the changes would include. What's the difference between CC-By-SA and MIT, and what about with attribution?
Broadly speaking, the difference is the "sharealike" clause of CC-BY-SA. Any derivative of a CC-BY-SA work must itself be licensed CC-BY-SA, whereas a derivative of an "MIT with attribution" work can be under any license the author wants.
There are a number of other differences in the fine print (eg. CC forbids DRM, where MIT doesn't), but that's the big one.