We are homeschooling a child who has significant strengths and significant weaknesses. We have focused on getting his weak areas up to the level where they won't unduly impact his ability to function in daily life, to the extent we can without unduly cutting into his time to pursue his passions. We have found that we can leverage his strengths to help him find ways around and through his weaknesses.
If your child doesn't have areas of weakness that rise to the level of disability, I wouldn't worry about forcing them to try to be "well-rounded". I would focus on making sure that they have regular exposure to a wide range of unfamiliar topics and experiences, because you can't develop passion or skill something you've never tried, and ensure that they are allowed to pursue things that they find they enjoy but don't easily excel at if they choose.
Thanks to the posts in this thread, and an article I read about the economy increasingly functioning to replicate the expertise of a few specialists, I've decided that hindering growth of a talent in exchange for well-roundedness is probably not a good approach (assuming that talent is marketable).
Along the same line of thought as posted above by aculady, it seems like a weakness could potentially hold back development of a strength, at which point working on the weakness accommodates the strength. For example, it seems that many gifted children who are skipped ahead a number of grades in elementary school have difficulty writing as much as is required in the later grades. If a child who is a candidate for grade-skipping has a weakness in writing, it could be advantageous to work to improve his or her writing well before that opportunity is presented.
Until recently, my daughter (2.5) hadn't demonstrated a mathematical aptitude to match her verbal aptitude... but now she has. I'll still be on the lookout for strengths and weaknesses though, and at least now I feel like I have an approach.
