My suggestions are more in line with balancing the warlock in line with classes like barbarian, martial adepts, and PF paladin. I'm going for a more general fix, not just a straight conversion. Don't worry about making it as powerful as wizard; that's not going to happen unless you start giving out Time Stop invocations or something.
Lack of invocations is one of the biggest problems of the warlock, since invocations are needed to provide options for them, but you only get 3 at each level and many of them are fairly fixed (See Invisibility, Fly, Chilling Tentacles, etc). Since most invocations aren't that powerful anyway, giving more invocations only provide more versatility, which is something warlocks need. Likewise with the skill points, since warlocks are set up like skill monkeys/half casters, yet they only get 2+Int per level. Extra Invocation may work, but you shouldn't force anyone to spend feats on what they should be getting as class features.
The reason resistances need to be boosted is that they are worthless normally; at 10th level, you would normally be able to stop 5 points out of a 10d6 fireball, taking on average 30 damage rather than 35. And fireball is only a 3rd level spell! An empowered fireball, perfectly usable by a 10th level wizard, deals on average 52 damage, becoming 47 after resistances; preventing less than 10% damage in situational places is not a worthwhile class feature. And resist 10 at 20th level is just utterly laughable. Resist Energy, a 2nd level spell, works three times better than the warlock's 20th level capstone.
As for Complete Mage, it's true that it does have quite a few underpowered invocations, but there are some gems in there. All Seeing Eyes and Otherworldly Whispers, for example, are fine as least invocations, and others can be situationally useful. The main goal is to expand options (not to mention the detach eye/hand ones are just cool). Most of them are not absolutely necessary though, so they're a lot harder to fit into your list unless you have more invocations as per my previous suggestion.
Oh, and yeah, easiest is to just use refluffed Dragonfire Adept.