When Tennyson succeeds Wordsworth as Poet Laureate, his words about Wordsworth gain even more significance and meaning.  Overall, the words speak to the idea that Wordsworth sought to construct a transcendency through words and language.  The idea "uttering nothing base" helps to bring out the idea that all of Wordsworth's writings helped to construct meaning of a transcendent notion of the good.  The sentiments that Tennyson sees in Wordsworth's writings are the idea that art, human beings, and consciousness are to be viewed as what can be, as opposed to what is.  The lack of "base" writing in Wordsworth brings credence to the idea that what Wordsworth sought to do is to transform reality and the people who read his work.  Tennyson understood that Wordsworth's lack of uttering "nothing base" resides in both content and technical form, representative of work that aspires to be more than simply all human beings can do.  Tennyson's words about Wordsworth were deliberately chosen.  Consider how Wordsworth saw his view as a poet and as an artist:

A poet is a man endowed with more lively sensibility, more enthusiasm and tenderness, who has a greater knowledge of human nature, and a more comprehensive soul, than are supposed to be common among mankind.

There is "nothing base" in this conception of artist and of poet.  There is only transcendence, something that Tennyson knew when he succeeded him as Poet Laureate in 1850.