I was basing that on my single-player experience. Wars happen more rarely in BNW, but they still seem to be very persistent when they actually happen - that hasn't changed much since G&K.
In my experience with SP mode, once you capture 2-3 AI cities and have a military force to threaten to take more, the AI (even Shaka) will agree to peace terms. I have personally never been involved in long wars of attrition.
I rarely bother capturing workers, and I always want to keep one or two on standby in case pillaged improvements need repairing. It's certainly an inventive idea, I just doubt I'd get more than a couple of units out of it in a game.
Sure, different players have different play styles. But a player directing a Vietnamese civ would also have the
option to build/purchase a worker quickly/cheaply --but only during times of war-- who can then be upgraded in the next turn to a Vietnamese UU that has relevance (for balance purposes) only during a certain era, e.g., the Fire Lancer.
I think a unique resource feels different in that regard from some of the other clumsy uniques. A unit or building is something produced; a resource is something in the landscape to exploit. Indonesia skirts close to the edge with pepper, certainly (and in general I think the unique resource idea is awkward), but even that is less ubiquitous in its production than rice - there are a few historical core sources, and while Indonesia isn't the primary one it's among a small number of major pepper exporters.
A mildly interesting side note: Vietnam is currently the world's largest producer and exporter of pepper.
More to the point, this discomfort with having the hypothetical Vietnamese civ be in possession of a unique bonus resource as commonplace as rice could be salved, perhaps, by my idea of tying it to generating happiness if rice is
planted (i.e., it's not an automatic, like Indonesia's pepper; plus, it can be pillaged) on a marsh or floodplain tile within the territory of a city that
also has a Water Puppet Theatre (WPT). Again, this is meant to reflect the development of water puppetry as a past time connected to rice farming, and their undeniable importance to the development of Vietnamese culture. Game play-wise, it would (A) strongly influence the selection of city placements for a player directing this Vietnamese civ (with the side benefit of making marsh tiles useful), and (B) make rice planting only especially beneficial to the Vietnamese if they researched Acoustics to build the the WPT.
Rice and water puppetry would also tie in well with the
theme of water as the central characteristic of a hypothetical Vietnamese civ. After all, the third attribute I proposed in an earlier post, namely, military resistance against invaders (let's call it Thang Long, "Ascending Dragon," which has a rather interesting meaning), is also strongly connected to the theme of water. (Examples: Vietnamese victories at the First and Third Battles of the Bach Dang River in 938 and 1288, respectively, depended heavily on the Viet side's knowledge of local tides; and the Vietnamese venerance for the
divine turtle that granted King Le Loi a magic sword to drive away the Ming.) I just hope that the idea of a theme that ties the hypothetical Vietnamese civ together, plus interesting dynamics like the ones I and others have proposed, will be enough to persuade the Firaxis developers to create a Vietnam DLC civ. I, for one, would be quite happy with such a development.