Many of the hexes are there simply as nods to famous witches... do you want to copy Baba Yaga's Hut? There's a hex for it. Do you want a witch that rides you in your nightmares, as some supposedly did? There's a hex. Do you want a witch that creates poison apples and can put princesses to sleep forever? Covered. A witch who sniffs out children in order to cook and eat them? It's all there.
That said, I agree that too many of the hexes are villain-oriented, and useless for most adventuring PCs. Luckily, as you said, there are enough decent choices that a good character is still possible.
I recently rolled up a 1st level witch for a new Pathfinder Scarred Lands game that our group is starting in a few weeks. I made some different choices than your guide suggested... they may or may not all be optimal, some were done to fit the character's background, style, Patron, etc, but I did try to make a useful character.
Race: I chose Elf for several reasons, both for flavor and rules. The biggest benefits to me were the stats (+2 Dex, +2 Int, -2 Con) and weapon familiarity with longbows and rapiers (among other weapons). Rapier and Longbow are significantly better than a light mace and crossbow, and I plan to be using weapon attacks a fair amount, at least in the early levels, until I get more attack spells.
Attributes: The DM gave us several attribute spreads we could select from, and the one I chose gave me the following stats after Racial modifiers:
Str: 10 (0)
Dex: 18 (+4)
Con: 9 (-1)
Int: 17 (+3)
Wis: 14 (+2)
Chr: 12 (+1)
Now, I'm sure you're wondering why a primary caster like a Witch would put her highest score in something other than her casting stat... that's not something you see every day. But I chose a Patron of Agility, and my 1st level feat is Weapon Finesse (which goes well with the Elven proficiency in rapier if I need to melee, giving me a +4 on both melee and ranged attacks, Initiative, and AC and Reflex saves, not to mention all the Dex-based skills I'm picking up). In effect, Dex therefor gives me 6 important bonuses, while Int only gave me skills and save DCs on my spells. Since I'm starting out more focused on healing and buffing rather than attacks, that won't hurt me very much, and by the time I have enough attack spells and hexes for it to matter, I'll be putting my 1st Attribute point increase at 4th level into bumping the Int to an 18 as well. But for the first 3 levels, for this character, I felt Dex was just more important.
As for the other stats, I wish I could have had a higher Con, and I may raise it later, but we are going to be a fairly city-focused campaign to start with, and so I wanted my social stats and Sense Motive, Perception, etc to be above average. With Weapon Finesse, Str lost some of its importance.
Familiar: With a Patron of Agility and a focus on Dex and stealth, I just had to choose a cat. He's a long-haired grey mouser named Fafrd.
Skills: An emphasis on Dex and Int-based skills, but also taking some social skills because this campaign is supposedly going to be city-based and full of intrigue and social gamesmanship.
Hexes: I chose Healing as my 1st Hex. Magic items will not be in great supply in this game, and prices of most items will be several times their usual costs when they are available at all, we were told, so the usual "buy a wand of curing" won't be possible for quite a long time. This lets me cure each party member once per day for free, and at 5th lvl it becomes a cure moderate wounds each. The larger your party, the more useful it is... with at least 5 party members in our group, it's like having 5 extra free Cure Lt Wnds (and later Cure Mod Wnd) spells memorized per day (more if you use it on NPCs for cash as a day job, or on hirelings, mounts, etc).
Later Hex choices will include (in no particular order) Flight, Disguise, Misfortune, Evil Eye, Cackle, Beast Speech, and Slumber. Note that although you rated Slumber as the best Hex, it's a terrible choice at 1st level, IMO, because it only last 1 round per level of the witch, not minutes like the Sleep spell. Putting someone to sleep for 1 round is about as useful as taking Summon Monster I at 1st level, when it just lasts a round... it's a solid choice for later, but not so much in the early levels. I instead chose the Sleep spell to begin with, as it can affect multiple creatures at low level, and it lasts for minutes. By the time it runs out of usefulness, the Sleep Hex will be worth taking.
), 1 round IS enough to get a coup de grace in. So it is useful at level 1. You just want to use it at the right moment, once an ally is already in position for the kill. Even aside from that, you'd want to delay or ready your action as needed. A simple standard action slap wakes someone up; you want to have the Slumber hit right before an ally's turn comes up for the kill shot, so the enemy's friends have no chance to save him.
