It looks like they have already started doing that. Cyanogen has recently announced a partnership with developers Boxer, who for those unfamiliar is behind the Boxer email client. In the upcoming Cyanogen OS 12 update, Boxer will now be the default email client which means that if you were hoping to see Gmail or the default Android email app, you would be disappointed.
Granted there will need to be some adjustments made by users if they were to use Boxer as their default client, but the good news is that the partnership with Boxer will see it come with its premium features. This includes Exchange support, multiple accounts, and quick reply features. Users will also be able to customize LED colors according to email accounts as well as gestures.
The Android version of the app is free by default (versus iOS which costs $4.99) so you can go ahead and download it to get an idea of what to expect, but you will have to pay if you want to unlock all of its more advanced features.