I think we are on the same page with most things. The math example was an extreme. I didn't mention that while I CAN do them, i don't do them fast or well. It's like the formula's in the book - I prefer them to be clear, straightforward and logical for the game system. Some of the rules aren't that way and it's not that the can't be done, but they could be designed better.
I started collecting my Traveller stuff from day zero. I have many (though not all) of the MGT books. I, too, don't want to see constant changing of the rules and tossing out everything that came before. My (well one of) biggest gripe is that as the rules get republished it's very rare to see things added. Err, well, that's not totally true. CT --> MT made a LOT of changes. At first the added tech and options seemed great. Then when you started getting into designs I started to find the opposite was true, that there is/was TOO much of a good thing.
The CRB has to cram a lot into it to make the initial game system playable. I get that, and I'm ok with the price. But that doesn't give any publisher a free pass on getting things right as far as the rules go. That's what they are there for after all.
I guess we should probably get back to the thread at hand...
I think, overall, the design system would benefit from a revamp of the overall tech. There are lots of rules, changes, errata and new tech spread across a LOT of books. I have the Anderson & Felix Guide to Naval Architecture (and sadly haven't had the chance to read it cover to cover) but I think this is a great direction to head. Players generally tend to min/max their designs. But for most companies they aren't going to put armor on a freighter, or even defensive weaponry if they can get away with having none because all of that costs money. I think the space in the MGT books really doesn't allow say half a page of discussion on thoughts and philosphy on armor, when to armor, why to armor, how much, etc.
When you break that down into materials and such, and with things like a/g, there's no reason you your 10ton tank that can't be as tough or more toughly armored than your 200dton free trader. If you use the same materials there shouldn't be any difference - except in the actual damage resistance the intended vehicle is capable of. Which leads us back to the armor adjustment by displacement. It makes sense that a much larger ship's armor factor gets skewed with sizing, and therefore adjustments make sense to keep everything somewhat equivalent. And somehow keep them simple enough, too.
Though good luck to anyone who can accomplish all that!