I played a lot of CS1 Mu. I think the new CS2 Mu is nice (after playing her for a bit), but she needs some getting used to.
There are some proration changes that require you to adjust to... for example, the corner combo seems a bit tweaked. Her chain into 2B from j.2C is a bit easier which is nice, her guns are less dangerous to setup which is nice... but she also feels a bit more sloppy and less structured. The new corner bounce mechanic is nice, but also seems to hurt her mid game a bit.
Overall it seems like her damage potential went up, but it will take a bit of time to adjust to her.