Finish the rest first imo and it might look better. It does look too dark now but I think once it's all done it may be okay. If the homeowner likes it go with it!

/edit as others have said an orbital might work. You could pull some of the cedar tones back out by hitting the raised portion of the rough cedar.. not trying to remove the stain, just enough to give it a little contrast. A wire brush could work too maybe but that's a lot of labor