A manual really wouldn't cover that sort of thing in any significant depth either way; it's not a strategy guide.
I really have to take issue wiht this statement. Indeed, it really annoys me. Readily providing the various tech trees (the most ballyhooed of the new TA features) either in a manual or ingame is not the function of a strategy guide; indeed, it is frivolous to so suggest IMO. The lack of this information has been a thorn in my side all through beta. Like others here, I really like Stardock for their basic games, dedication to updating games beyond (probably) economic good sense, excellent customer service, and generally forthcoming attitude to the community. I bought TA largely to support Stardock, even though I don't expect to play it a lot. However, one of their glaring faults is poor documentation. Not only are the manuals poor (generally covering only a fraction of gameplay, and that often in a conusing, if humorous, manner) but ingame information is very poor and the UI is below average. For example, the research screen, while somewhat improved in TA, is still ridiculously poor to vavigate.
To see how this can be done right, it is only necessary to go to Civ4. That manual, although inferior to older Civ manuals, is still decent and miles better than the GCII manual. The ingame information is even better. Admittedly, it took Firaxis a couple of patches and two expansions, but the Civ4 UI is close to 4X nirvana. Information is easily found everywhere (and in readable fonts). The Civolopedia--a feature that GalCiv needs badly--is wonderful. (BTW, the Civilopedia was a mess at Civ4's rushed launch, but was fixed in the first or second patch. On the negative side, I should add that Firaxis badly screwed up a patch to the most recent expansion, inadvertantly dropping some crucial UI information; this bug was fixed by a fan created patch but shamefully has never addressed by Firaxis after many months.). I realize that Stardock does not have the resources to polish its games that Firaxis does, but the gap should not be as large. A useful comparison is to Paradox, another small niche dev/publisher of strategy games. It's most recent games (EUIII and EU:Rome) come with thick printed manuals that are far superior to Stardock's manuals. And Rome also provides registered users with a very comprehensive downloadable srat guide. Even the older Paradox games with less good documentation (like Victoria) still are superior to Stardock. In fairness, though, Paradox UIs are not particularly well done. (I should note that while Sins' manual continues the poor Stardock tradition, the ingame UI is quite good.)
Regardless of the tone of the above, I really like Stardock and GalCivII. Nothing is perfect and I can put up with the poor documentation and UI, which are outweighed by so many pluses. However, I realy could not let a defense of this obvious flaw go unanswered.