Normalized Migrate (NorMi) is intended to simplify most Drupal migrations by assuming the source database is normalized for migration, i.e. one table per migration. The following diagrams provide an overview of how using NorMi differs from using the migrate module directly:
When migrating from a database, NorMi moves all the work of migration into a query that converts the legacy database structure into a normalized (for migration) structure, i.e. one table per entity. That standard source structure makes is possible to entirely automate the code part of migration, which NorMi does.
As a bonus, this also allows migrating from an auto-generated CSV file, so content can be populated simply by editing a spreadsheet, a familiar process for many content editors.
The interface for NorMi provides selection tools for which items will be migrated, e.g. which content types or taxonomy vocabularies, as well as which steps in the process you want NorMi to automate, e.g. create database tables, create module code, create CSV files, etc.