Under the strictest definition of the term, yes the Church would be considered Protestant. Considering the term is actually "...a member or adherent of any denomination of the Western Christian church that rejects papal authority..." Even that, with the words "the Western Christian church," could most certainly be interpreted as the Catholic Church alone. Which the LDS Church did not derive in any way from the Catholic Church.
So, Protestant Churches are usually considered to be those that came straight from the Catholic Church in the 16th and 17th centuries. In that case, the LDS Church is not Protestant.
You'd have extend that into the 18th Century. Methodists were not a separate denomination until the late 1700's. Methodists are generally considered Protestants, though their "roots" are in the Anglican Church.
