Text: break :: Text ->  Text ->  (Text, Text)
      breakBy :: (Char ->  Bool) ->  Text ->  (Text, Text)

One consistency problem I see with this is that the ByteString versions permit breaking on a disjunctive pattern (e.g., \c -> c=='a' || c=='q') whereas the Text version would require multiple passes to perform these queries, since it takes a Text instead of a (Text->Bool).

Other than that, I do agree with the philosophy of the "deliberate and sensible" differences. Though, given the philosophy that these aren't Char-wise operations, why does Text.breakBy accept a (Char->Bool)? Is this just an optimization for common cases like breaking on Unicode-defined whitespace codepoints?