That isn't an error. The patron spells are numbered by the class level (1-20) you get them. The spell list is numbered in the actual spell level (1-9). You would get access to confusion on the regular spell list at level 7.
Sorcerers basically get +6 skill ranks thanks to having UMD and bluff as class skills. Wizards will get +level skill ranks every time they raise INT by 2 points (typically 8th and 16th level). I think the 40 extra skill ranks at 20th level is more than 'a hair of an advantage'. Sorcerers can be good (great even) at 3-4 skills. A wizard can be great at 7-8 skills, or even good at 3-4 and competent at another 7-8 skills. Even more, the wizard can afford to get good in very useful non class skills (like Perception or Stealth), where the Sorcerer cannot.
You don't get 40 extra skill points at 20th level. The extra skill points are gained as your INT increases (and doesn't apply to magic item increases - the increase must be a permanent increase). So, if you gain a +1 int modifer at 16th level, this will only give you 5 more skill points, not 20.
Actually, that isn't the case. Ability score increases apply retroactively.