Regarding Heller kits - there's a tremendous amount of variation in how they handle "wood grain." (That's true of how most manufacturers handle all sorts of details - but it's particularly conspicuous in this case.) In the first generation of Heller kits, the "grain" was represented by more-or-less arbitrary scratches on the molds, which then showed up as raised lines on the parts. At about the time the Soleil Royal and Reale appeared, the moldmakers started making an effort to represent genuine grain-like shapes (including knots), and making the necessary scratches on the masters (rather than the molds), so the detail on the finished product was countersunk, rather than raised. It was pretty heavily overdone, but much better than the first kits the company made.
In this area as in so many others, the designers unfortunately didn't do their research. Sometimes they scribed the edges of "planks" in reasonable places; sometimes they didn't. In some Heller kits from the seventies, the "deck planks" are more than a scale foot wide. The head knee of the Soleil Royal, if memory serves, has "grain" engraved on it in such a way that it looks like it's made entirely from a single board. And the ship-of-the-line Superbe looks like its entire hull was hacked bodily from a single log. (I'd like to see the tree.)
By the time they got around to the Victory, the Heller artisans had learned a great deal. The planking on that kit is beautifully done - with each plank, straight or "anchor-stock" style, in the right place.
The hull and decks of a sailing ship present the same problems to kit designers as the wings and fuselages of aircraft do. Even the finest of the aircraft kit manufacturers puts surface detail on its models that's far out of scale. The grooves in the surface of a Hasegawa or Tamiya 1/72-scale airplane scale out to somewhere in the neighborhood of 1/2" wide and 1/2" deep. Real airplanes don't have grooves like that on them. I certainly agree that most of the wood-grain effect on most plastic sailing ships is overdone. But I'm not so sure I'd want to see such detail eliminated entirely.
Another point that comes up sometimes in this context concerns the grooves beetween hull and deck planks. In real life they're actually wider than many people realize. In the eighteenth and nineteenth centuries it was standard practice to chamfer the edges of the planks, in order to leave a substantial groove between them to receive the caulking that made them (more-or-less) watertight. The typical wood sailing ship did in fact have grooves in its hull and decks. The caulking, when fresh, would stand slightly proud of the surface; as it wore away the surface became virtually flush, and eventually shallow, three-dimensional grooves would show up as the ship worked and the caulking got older. When that happened, it was time to think about recaulking.
In contemporary photos it's usually possible to see the edges of hull planks. The kit manufacturers overdo it, of course, but I don't think I'd want to depict a hull on 1/96 scale as perfectly smooth.