Coming to the K-12 Core production for Education as an existing RENXT and FENXT customer, I have been thus far disappointed with the customizations and mail house readiness of lists that originates with the ability to manipulate fields. Here are a few touchpoints:
The Household feature, while helpful, cannot be used for school-wide mailings as the Address is exported as a single field, not broken up into Street, City, State & Zip, as is most common.
Furthermore, the Household export cannot be used as is because it export with some sort of page break between the Street line and City/State/Zip line, and so a text-to-columns separation cannot be run.
That break should not exist, and columns should be able to be added so that the export can be usable.
Similarly, emails to Parent "personas" can only be categorized as primary or CC, and only tagged as active or bad, when it should mirror RENXT and with labels such as Home/Work/Alternate and be marked as active/inactive with use dates.
And finally, there doesn't seem to be a way to edit or append the default set of fields; existing ones for Home District, Elementary School and Parish are needed by my institution. Everything should be accessible under the Tables mapping.
The bottom line is that while I'm happy to do the legwork needed in set-up or after the fact in Excel, Core does not presently give me either option. The environment should be as limitless as an institution's needs in terms of customization.