I agree with virtually everything in Spelunko's post above. I can, however, add a little about the history of plastic sailing ship kits.
Revell got into the sailing ship game in 1956, with its U.S.S Constitution, Santa Maria, and H.M.S. Bounty. Apparently one of the first decisions the designers made was that plastic modelers needed help with shrouds and ratlines. The Santa Maria kit wasn't much of a problem; the designers figured (though there's some debate about the point) that the original didn't have ratlines. But the other two prototype vessels obviously did.
The Revell folks thereupon came up with an idea that probably seemed brilliant at the time. They included in the Constitution and Bounty kits some odd-looking things called "pre-assembled shrouds and ratlines," made of thread which had been sprayed with some sort of flexible plastic. The shrouds and ratlines for the whole ship came fastened to each other, in a sort of grid arrangement. The modeler was to cut them out, using a pattern printed on the instruction sheet, and attach them to the model.
In my personal opinion it was a lousy idea from the start, for at least three reasons. First, the plastic-coated thread was slick and shiny; it didn't look the least bit like rope. Second, the thread used for the shrouds and ratlines was the same diameter. (In reality ratlines almost invariably are much thinner than shrouds.) Third, it was almost impossible to set the things up tightly. The material was hard to tie in a knot, and cement wouldn't stick to it.
I suspect these hokey things were largely responsible for giving the plastic sailing ship the rotten reputation it had among serious modelers for such a long time. When serious modelers saw pictures of models built "out of the box" from Revell kits, they concluded that the kits were only capable of producing things that looked like toys. Unfortunately one other firm, Airfix, adopted the same idea. To my knowledge, no other manufacturer ever did.
The plastic-coated-thread "shrouds and ratlines" were included in most Revell sailing ship kits throughout the fifties and sixties. Even the big kits - the 1/96 Cutty Sark, Kearsarge, and Constitution, along with their re-release cousins - had them.
Somewhere along the line (I think in the late seventies or early eighties - but I could be wrong about that) somebody at Revell either figured out that the plastic-coated-thread looked like s![Censored [censored]](/FSM/CS/emoticons/icon_smile_censored.gif)
t or concluded that they were too difficult for inexperienced modelers to rig. (I suspect the latter.) The hideous conglomerations thereupon disappeared from the smaller Revell kits (the ones that were about 18" long), to be replaced by rigid, injection-molded plastic units that just may have managed to look even worse. (The plastic-coated thread ones stayed in the big, 3-foot kits; so far as I know they're in the latest versions.)
The Great Ratline Problem is one of the plagues of the plastic sailing ship kit industry. The manufacturers haven't really figured out a solution to it. The attempts have ranged from the Revell/Airfix approach to molding the shrouds and ratlines in flexible plastic (Lindberg) to producing a ridiculous conglomeration of jigs on which the modeler is supposed to "weave" the ratlines (Heller's H.M.S. Victory). To my notion the best approach was the one adopted by Pyro, which told modelers how to rig the shrouds (to plastic "combo units" that looked reasonably like deadeyes and lanyards) and ignored the ratlines completely.
The truth is that the problem is, by definition, in the lap of the modeler. The manufacturers can't solve it.
I'm aware of two good basic ways to rig ratlines on a scale ship model. The first, of course, is to rig them like the real ones were, using either thread or wire and tying it with a clove hitch around each shroud. (That really isn't as difficult as lots of people think, as long as the scale is reasonably large. An it doesn't take as long as most people think, either.) The second, which works quite well on smaller scales, is the "through-the-shrouds" method. Rig the shrouds, then thread a piece of the finest thread you can find into the finest, sharpest needle you can find. Shove the needle through each shroud in turn. When you've gotten it through the whole gang of shrouds, put a drop of white glue on the first and last intersections. Let the glue dry, then cut the ratline off flush with the first and last shrouds. If done carefully, this method can produce really nice results.
On very small scales (smaller than, say, 1/16" = 1'), some modelers have gotten extremely impressive results using fine wire and either adhesive or solder. I haven't used either of those techniques myself, but I've admired both of them in the work of other folks.
Back to the Revell kits. Many of the those sold on e-bay are quite old; they date from the Plastic-Coated-Thread era. In most cases, when the injection-molded shrouds and ratlines replaced the coated-thread ones Revell didn't make any other changes to the kits (other than the instruction sheets - which frequently lost their text in favor of internationally-readable pictures). Regardless of how the shrouds and ratlines are made, most serious ship modelers throw them (along with the vac-formed plastic "sails") in the trash before leaving the hobby shop. So if your interest is in using a kit as the basis for a serious scale model, the vintage of the kit probably doesn't matter much.