What was/is the behavior without this work in place? I.e. why is the regular RAI type extractor insufficient?

There are two reasons the regular RAI type extractor is insufficient:

• Unfortunately, ExtendedRandomAccessibleInterval does not implement RandomAccessibleInterval - if we had a RandomAccessible type extractor, utilizing getType(), then we likely wouldn't need this for much, practically speaking.
• In terms of information gained, ERAI has a second type variable that cannot be reified without a dedicated TypeExtractor plugin.

The second would not be fixed by some broader RandomAccessibleTypeExtractor which used getType (which, as an aside, we should totally do once that code is ready)