http://nypost.com/2014/01/15/beautiful-star-mueller-an-early-tony-favorite/ He says the early favorites to fill the category are
Sutton Foster in VIOLET
Idina Menzel in IF/THEN
Jessie Mueller in BEAUTIFUL
Kelli O'Hara in THE BRIDGES OF MADISON COUNTY
Michelle Williams in CABARET
He doesn't mention the competitors from JANIS JOPLIN, ROCKY, or BULLETS OVER BROADWAY.
"The Spectacle has, indeed, an emotional attraction of its own, but, of all the parts, it is the least artistic, and connected least with the art of poetry. For the power of Tragedy, we may be sure, is felt even apart from representation and actors. Besides, the production of spectacular effects depends more on the art of the stage machinist than on that of the poet."
--Aristotle