I believe that extremely realistic lures make a big difference especially when the fish get a good look at the bait. However I feel that most baits that are thought of as realistic, are not realistic to me. To be realistic it needs to be shaped like the species its trying to replicate. It needs to be the right size. It needs to be painted correctly, and the action needs to trigger a bait. Notice I did not say the action has to be realistic, because it doesn't have to be. If it swims realistically thats good to, but there are baits that don't swim naturally and they get bit. I will use the stocker trout as an example. It has the right shape, close enough colors, and the right size. It lacks details but it is meant to be fished deep and faster then most swimbaits so the fish don't get a great look at it. It does not look like a natural healthy trout when it swims. It has some body wobble and with the one joint it is not as fluid. Does it get bit? yes it does and that's what matters. Something about its action triggers bites. Maybe it looks injured?
Back to "realistic" baits that I don't think are realistic. A spinner bait with a detailed head, is not realistic, it still looks nothing like a fish. It looks like a spinner bait. Most crank baits that have realistic finishes do not look realistic to me. They look like a crank bait and swim like a crank bait they just have a fish painted on them. I am not saying they don't work because they do. I just don't consider them realistic. Most of the time when I am targeting big bass, I am fishing slow and the fish can get a good look at the bait so I want the bait to look as close to a real bait fish as possible. The faster and more erratic your presentation is, the less realism matters. It matters even less on younger, smaller bass. I also believe it matters in waters that are not clear. Fish see better then we think in their environment. I think they can see great in stained water. Unless its chocolate milk or at night then I think they still rely on sight as there #1 way to hunt food. Funny thing is back when I used to fish jerk baits( I think that's what they are called) I did not like the ones with fish painted on them. I liked the Silver foiled, black backed, yellow eyed baits. They just got bit a lot more. If I was to fish like that again I would take all those Rapalas and paint the tops olive green. It's never made sence to me to paint the top of a bait black when its trying to resemble a fish. I have never seen a bait fish that was black on top where I live. Sorry for the long winded rant/reply