For many years main stream Christian churches were called Protestant as a distinction from Catholicism. Today these churches call themselves Evangelicals. Is this change due to a realigning of values and subsequent blurring of the original doctrines of the early Reformers?
the term evangelical comes from the Greek word for the gospel, euangelion.
evangelicalism is, as i understand it, a movement among protestant denominations shifting emphasis to the gospel, dating back to the 1700's with puritan movements.
it wouldn't be right to say that this in principle is blurring the doctrines of the original reformers; the term itself can be traced at least all the way back to Martin Luther who talked about "the evangelical Church" as a distinction from the catholic church, and they all held scripture and the preaching of the gospel above traditions, councils and the papacy: this is what basically separates protestantism from catholicism, the gospel vs. the traditions and organized leadership.
in principle is one thing but in practice is another. what evangelical means to one church can be at least as different to another as what the gospel means to one church could be from another, and the term has become so vague that to a lot of people it just means "a white member of the republican party"