I have come across so many items with exposed zippers (tops, dresses, skirts) that I have used kind of a common-sense, it depends approach.
Such as: What are my options? If perfect dress fit at good price point at a time I'm having trouble filling a real need, would go ahead. Not as keen on having an exposed zipper in a major investment piece or budget stretch, and that may speak to versatility rather than trending issues. Or if I know there are lots of hidden zips out there and there's no particular need for exposed, I prefer hidden. Also, I have to like the exposed zipper. Some look weird and detract, to my eye, and others fit in better. And fit in with the way I will wear the garment.
My odd exposed zipper story is this: I bought a couple of tops from BR with exposed back zippers and princess seaming which allowed for a really nice, tailored fit for a top worn over the bottoms in comparison to a knit top. The tops were about mid hip and my jackets mostly covered them, but maybe a half inch peeked out sometimes, but the tops were in colors blending well with the jackets, so almost couldn't tell, anyway, looked fine. Great--a perfect sophisticated outit. Then one day I was checking the back view in the mirror and kept seeing something "winking" or flashing at me. Lo, it was the metal bottom of the zipper catching the light everytime I moved a bit and the jacket rode up 1/2 inch, disrupting an otherwise almost perfect color match/blend. It was funny because it was right around my tail bone, and it was off and on, and that seemed to make things more odd! I did try "coloring" that bit of metal to make it less reflective.