Mace was pretty close to falling too with his "We have to kill Palpatine in cold blood NOW" attitude during his final battle. Granted, he was right, but he was still veering from the Jedi way of doing things.
If anything Vergere was closer to that Force users in general should have been trying to do rather than polarizing into Jedi and Sith. She would have worked well with the likes of Revan and the Exile, had she not been skewed by her years in Vong captivity. Her views on the Force were only wrong in that they differed from Jedi teachings, which we can objectively see as flawed.
For example, if Anakin had beed raised under the Order Bastila helped to forge after Revan's departure, his marriage would have been acceptable and he most likely would not have fallen. The Revan-age Order, Old Republic Order, and Luke's New Jedi Order all had differing views on the Force that would have caused conflict between each group, yet dissenting from the existing order of the time automatically made you wrong and on the way to the Darkside. Frankly, that's BS as what might be seen as wrong to one order was perfectly acceptable to another.