You're technically correct that Ellen G. White is a co-founder of the SDA church along with Joseph Bates (I would have to do some research, but I think that he was the #1 leader), but the church was not formed to follow the teaching of Ellen G. White. A group of Christians from various religions had studied the Bible and came to the conclusion that Christ's second coming was in 1844, I can't remember the specific date right now. They sold all of their stuff and were sitting on a hill waiting for His return. This is known as the Great Disappointment and it pre-dated the SDA church. As a result of that event, some of the believers left Christianity and other determined to further study the Bible and figure out where their error was. This group eventually became the SDA church.
Also, as a side note, she referred to herself and a "lesser light," never to be taken above the Bible.
Have you ever read one of her books from cover to cover? I will be honest and admit that I haven't, but I have yet to find anything that she wrote that I wasn't able to compare with the Bible and see that it matched. The other SDA's on the board that were raised SDA will probably all agree that the older generation went overboard with her writing and as a result many of my generation avoided her writings while growing up. I am almost 28 and I am just now warming up to her writing. My beliefs are based on the Bible alone.
As an interesting side note: There is also a ton of history to match the Bible facts (a list of about 10 things) about a prophet. Did you know that true prophets go into a trance/coma thing when they are in vision and also they stop breathing? Both of these are historically documented for her, I don't know all of the details but I would be willing to do some research if you want.
