Microsoft said: "You can turn off Input Personalization at any time. This will stop the data collection for this feature and will delete associated data stored on your device, such as your local user dictionary and your input history. As Cortana uses this data to help understand your input, turning off Input Personalization will also disable Cortana on your device. At
https://www.bing.com/account/personalization, you can also clear data sent to Microsoft, such as your contacts and calendar data, user dictionary, as well as search and browsing history if your device also had Cortana enabled."
Cortana is just a cute name for part of the indexed search feature, which is controlled by Group Policies:
https://technet.microsoft.com/en-us/library/mt577208%28v=vs....
Cortana is not turned on by default, and if she's not been turned on, there is no real benefit to removing "her".
However, for the record, I think Cortana is great....
Since Windows 10 is "Windows as a service", patched and maintained remotely, I'd expect random screwing around to be repaired remotely. However, it would be interesting to know if this will affect Windows' stability or performance. However, in general, it's probably a bad idea to mess around with the workings of things you don't understand.
This is one of the reasons I don't mess around with Android, or try to remove all the Google apps I don't want, or remove Google Now ;-)