What does "it is not a whit better than it should be" mean? Does the "it" here refer to "the literary character?"

Context:

The result of all these researches was a history of the province during the reign of the Dutch governors, which he published some years since. There have been various opinions as to the literary character of his work, and, to tell the truth, it is not a whit better than it should be. Its chief merit is its scrupulous accuracy, which indeed was a little questioned on its first appearance, but has since been completely established; and it is now admitted into all historical collections, as a book of unquestionable authority.

More:

http://www.online-literature.com/irving/2053 /
Hi,

After thinking about the meaning, I'd say 'it' is intended tor refer to 'his work'.

Clive
Hi

Whit just means the least bit, so it reads 'it is not the least bit better than it should be, with it, IMO, referring to either what you suggested--the literary character, or perhaps his work.
Students: Are you brave enough to let our tutors analyse your pronunciation?
Thank you