I think people who are coming in to tell someone they are wrong or state things as hard rules should remember that while there are some definite things in bad design a large part of great design is going to go to personal preference.
I can feel Brazil is well designed because I like synergy. PhilBowles, you can feel they are bad design. And it's all personal preference at that point in the thought process.
This isn't a conflict over design philosophy - no one's disputing that synergy is an important feature of good design. Or that Brazil has synergy. What I am saying is that Brazil's synergy is lazily-executed, and that synergy itself isn't sufficient in the face of other weaknesses in the civ's design (particularly that a "late-game civ" that gives you very little in most game stages has an inherent tension with Civ game design as a whole).
As for synergy, take the two following examples that achieve something similar:
Persia: A UA based on golden ages. A UB that increases happiness - which means quicker golden ages - at the same time as it provides a % bonus to city gold generation (gold generation that is improved during a golden age). It's a late-Medieval era building, and as a building remains in play for the entire game. As an additional touch their Immortal, one of the best if not the best early-game UU as it is, benefits from the UA. On reflection, Persia is one of the best designs in this regard.
Brazil: A UA based on golden ages. A UU that generates "GA points" from combat. Aside from being an uninspired design, this relies on actually fighting with the unit when nothing else about Brazil favours warfare. The UU is quite long-lived, but is still a UU and is very late game. Where Persia builds a bank (which it's going to want anyway, whatever its strategy) and gets on with things, Brazil is forced to build/upgrade units in the late game at exactly the time when it wants to be focusing on hotels etc. (but it probably won't be because it has to go down the wrong tech path to get the Pracina). The Brazilwood Camp is a better fit, but only has synergy in the late game (when it's not really any better than the Moai) while restricting to building near jungle tiles to maximise its utility, a tile type with poor resource output that's going to limit growth and development early in the game if you focus on settling jungles. If you don't, you don't get many camps.
Sweeden always throws me for a loop. I look at the AI.. ok if I have lots of civs on the map I can get lots of great people and.. wait throw them at city states? and then two UUs so am I combat now? Won't that make my great people stop coming in when I lack friends? I don't know where to go with sweeden.
Sweden has flexibility - nothing forces you to use both elements of the UA (any more than you have to use one of each type of CS to use Siam's), or to give the GPs you generate to CSes because you can. It's a civ that gives you tools that will vary with context. The suggested approach to increase GP generation through warfare is indeed one way to play Sweden, but because their UUs are rather late there's not a lot of synergy between the UUs and this approach beyond the simple fact that the Carolean, when you do get it, happens to be a very good UU. Bear in mind the Patronage tree - you can ally CSes with GPs, who will then give you GPs as a result of the Patronage finisher, who you can gift to get more CS allies, and more GPs, and...