I am starting this post Thursday night. Inspiration struck while washing dishes. I intend to finish Friday morning. We'll see how the thread goes.
I can't remember if I've posted on this topic before, and I'm too tired to reread my posts to see if I have.
Character strengths must be balanced by character weakness. I learned this, as I learned most of my character development skills, through role play. Specifically through the previously mentioned Marvel Comics Role Play Handbook. The game insists on limiting character strengths (a bit too much, in my opinion, considering the Marvel Comic hero pantheon) by including weaknesses.
Without those weaknesses, you have a "perfect" character, and those can be pretty boring. Superman is amazing at first glance, but he needs his kryptonite or there's no reason to turn pages.
I mentioned my Doctor Who companion Amy a few posts ago. Her strengths are immortality (more or less), photokinesis, mechanical empathy and beautiful eyes (I call them "crystal green"). Her weaknesses, however, are an emerging awareness of her lost humanity and a longing for the missing race that created her. Her story is one of perfect contentment shattered and the resulting chaos of picking up the pieces to discover, under all the genetic modifications, she is human.
I have another character, Catspaw, who is a chemical mutant. After an explosion altered her DNA, she developed hyper-elevated senses, iron-laced bones, and lightning fast reflexes. However, her hyper-sensitivity leads to migraine-like paralysis, pain and coma; her bones gain their iron from her own blood, which requires massive doses of iron supplements that cause other medical problems, and the trauma of the explosion creates a multiple personality that ricochets from manic to berserker as her blood pressure rises (something blood pressure tends to do in fights). In short, she's a mess: physically, emotionally and mentally. She's also a blast to write about, although I doubt I'll ever write anything for publication with her in it. She's one of my "for me" characters. Her strengths make her cool, but her weaknesses make her accessible. Without them, she's...too alien, even though she's human.
Caissa is educated, blessed with perfect recall, and physically tough as prairie scrub. But she is narrow-minded, naive and selfish. Those are the problems she carries with her into every dangerous situation in the book, and those are the problems that make the story interesting.
I've read books with characters who are too perfect. All the problems they face in the story are external. There's nothing wrong with that. Bad things usually happen to good people. But even good people have problems, and the better they are in some ways, the worse they should be in others.
I write stories about flawed people. All of them have something going on (even Indira, and she's the closest to perfect you'll find in Star of Justice). Yes, it does cause some sleepless nights, wondering how they're possibly going to make it out of those natural consequences, but natural consequences are interesting. And natural. And, consequently, naturally interesting to the reader.
Double-check your characters. The greater the strength, the greater the weakness. Give it try. You may hate me for suggesting it, but your readers will love you for writing it.