Honor, ever misjudged by the community, is easily the best tree if you're planning for conquest. The people who are saying Honor is bad are counting on the AI's poor tactical management to carry the day anyway without the Honor bonuses using one of the other two trees (ever played multiplayer? Taking cities is HARD against an opponent who plays the tactical game properly!). This basically amount to exploiting the bad AI and if that's how you want to play, fine, and in this case of exploit-gameplay Honor does indeed have less to offer, because Honor is a waste if you can win your wars anyway without it - but it isn't what the game is balanced around. Stuff like +15% combat strength from nearby melee units and the instant Great General makes Honor invaluable for early conquest. In multiplayer, where the catastrophic decisions of the AI aren't a factor, a Honor-player can bring the significantly more powerful army needed to take cities to bear than one using either of the other trees in the early game. You were asking about Shaka; Shaka should definitely default to Honor unless the game situation specifically dictates otherwise.
Calouste has a point in what he writes above about some some of the later Honor policies mostly being better 'later', but this is no different from the other trees which also feature policies that only really come into play once you've grown a bit. The real idea with Honor isn't to postpone it or to pick only a few policies from it, however; you are supposed to take it immediately and go beat up neighbouring civs/city-states. Same as Liberty and Tradition, the power of Honor wanes as game time passes so in most cases it isn't something you should postpone. Get it first thing, then get the army that will make it pay off for you: The Honor player expands through conquest - while the Liberty player is building cheap Settlers for cities, you are building cheap melee units with which to steal those same cities and bully Workers from independents.
