Do the import. The importer works pretty good, although it is not perfect. Cleaning up is much less work then doing it from scratch. For cleanup, you can do quite a lot in bulk, such as for example Schematic Editor / Tools / Edit Symbol Library Links to replace all the “eagle resistors” with native KiCad resistors.
A part of the reason you are getting more ERC & DRC violations, is because KiCad is stricter in some area’s, and checks for things that eagle does not. Learn what the violations mean and how to fix them. This will also deepen your knowledge of KiCad so you can use it more effectively.
It’s also possible you get a lot of DRC violations because either clearances or some other design rules are not mapped correctly into KiCad.
But do note I may be a bit overoptimistic. At the moment I’m toying with the import of an eagle project form github/adafruit and it crashes KiCad in various ways. If I know more I will post it in the thread below.