In the fourth printing of the Swords & Wizardry Core Rules, I'm doing the same thing I did with the WhiteBox and Complete Rules, which is to reintroduce the traditional saving throw matrix, although as an alternate rule. In the original versions of the game, I used a single saving throw category (basically just a "saving throw") for legal reasons.
Those legal reasons are a bit complex, but basically it's that the saving throw matrix involves a formatting and relationship between several concepts. When you pull in various copyright-law concepts, the saving throw table happens to be a place where several issues all come together. Since one of the copyright tests is the overarching "similarity of appearance and presentation," and since it's a matter of first impression how deep that test would drill down in an RPG, I considered the saving throw table to be a high-risk area even though each of the parts of applicable copyright law would pass the test. It's the problem, under that SAP test, whether the whole of the table became more than the sum of its parts.
Rather than make any sort of big changes inside the matrix, I figured for two reasons that it was better to go with the method I used in the earlier printings of S&W, namely, to use one saving throw category, but to give a fairly broad bonus to each class (well, not to fighters: I used them as the baseline, so they didn't need a bonus). The result is that there is a distinction based on character class, but it's not as detailed as the small distinctions made in the full matrix. To me, this is the overall target of the saving throw: to have general distinctions like "magic users save better against magic" rather than distinguishing the classes at the detail level of how they save against being turned to stone. The finer distinctions would virtually never come into play in terms of the decisions being made by the players.
The second reason was that a single saving throw category didn't cause a real problem when being used with original materials. The original materials almost never bothered to list the category - they just said to make a saving throw. Obviously, they still meant "in the appropriate category," but one can read an original module (or even the AD&D monster manual) without banging into something that isn't in the S&W rules. "Make a saving throw" written in an original resource still works just fine if you're using S&W rules, and if you're using the original rules with an S&W module, "make a saving throw" written in the S&W module is no different from what you see in the original materials.
However, the saving throw matrix is clearly something at the heart of the game for many players. I should have realized this during a conversation with Philotomy Jurament (Jason Cone) when I mentioned the single saving throw and the rationale (doesn't affect actual player tactics), and Jason still sort of wrinkled his nose and drank some beer. That should have been a warning, but I carried on with the original plan.
I'm still of the opinion that the single saving throw category actually works better than the matrix on a couple of levels, but that wasn't really the objective. The objective was to avoid what I considered to be an unacceptable legal risk. Since that time, I've found a particular format and approach to the saving throw matrix that removes (or at least drastically reduces) the chance that a judge might drill the SAP test down to a granular level instead of applying it at the "whole document" level, which is how I think it should work. But since this would be a matter of first impression, there's not a precedent right on point for me, and there wouldn't be one for the judge, either.
In any case, the saving throw matrix is now (or will be when I get the 4th printing done) in all of the Swords & Wizardry versions, as an alternate rule. And it will remain an alternate rule, because I still believe that integrating it into the "official" rules of a retro-clone presents a high legal risk of a copyright violation, depending on how some of the tests are interpreted on a matter for which there isn't clear, on-point precedent.
This is all just so that anyone interested can get an idea for why the matrix was originally excluded, why it is back in, why it's an alternate rule, and why I still prefer the single saving throw category for my own games. Overall, I think that knowing a bit about the background of this (alternate) rule in S&W may give players the freedom not to feel bound by this issue either way. Everything in S&W is a matter of choice, although I've tried to offer the real alternatives that have been used instead of just saying "if you don't like it, change it," without any suggestions. I think it's obvious that in any RPG the rules are a matter of choice, but it's one thing to just say that in the introduction, and it's another thing to deliberately organize the information to support not only this knowledge but also to point out where the major choices are, and the directions in which one might make house rules.
Anyway, this post was originally going to be more about the comparison of the two approaches and less about legal issues, but it turned out the way it did. That's what I get for composing in the new post box instead of writing and editing beforehand. And since a red bar just appeared at the top of the screen for a second, I'm going to hit "publish."