Homeschool or Not? ... Disadvantages of School

I posted here about the things that still worry me about homeschooling. Today's list, on the other hand, is the things that worry me about traditional schooling (at the early elementary level - I have others for when the kids get older, but I can worry about that later :). I'm not sure how much weight to give them, because after all, I and everybody else I've ever met has been through a traditional school system, and nobody's soul, personality or intellect seems to have been permanently warped by the experience! And I enjoyed elementary school a lot, myself. But for what it's worth, here is the list of "risks" I worry about if the girls go to a traditional school:

1. "Right" and "Wrong" answers. They would learn, firstly, that there are "right" and "wrong" answers, and that "right" is "good" and "wrong" is "bad." I would much prefer them to be seeking information for its own sake, because they want to know it, rather than because it's a "right answer" and will earn them brownie points / pats on the head / praise / self-esteem. I think kids (particularly ones who want to please their teachers) can develop a fear of "wrong" answers that very seriously discourages their willingness to take intellectual risks, explore multiple options, and damages their self-confidence. There's no need to have kids internalize that kind of thinking while they're still so young, and while their whole approach to learning is still being formed. Besides, when an answer is marked "right" or "wrong," that tends to be the end of the thought-process, whereas really there's usually a lot more to be said and thought about, in either case. And lastly, they would get used to the idea that someone else would be evaluating their work and pronouncing the verdict on it, whereas I would much prefer that they see themselves as very well qualified to judge their own work. Did it turn out as I hoped/planned/expected? Well, good. Or no, it didn't? Well then, what could I do about that? 
2. They would start to expect that someone else should be guiding their course of study and telling them what they should learn next, rather than learning to be guided by their own interests, and to explore and pursue the topics that they themselves find fascinating. I think that the best learning comes out of what you truly care about, and that self-directed study is far more likely to be inter-disciplinary than a course of study which comes pre-packaged into "math" and "science" and "language." All the research I've read emphasizes that the most exciting careers of the future are all going to be at the intersection of two or more traditional fields, rather than within one single discipline. When they're older, there might be plenty of things that they "need" to learn, even if they're not currently very interested in them, but for little kids, I don't think they "need" to know any particular set of facts. They need to know the joy of learning.
3. Not enough time outdoors if they're in school eight hours a day.
4. Not enough physical activity if they're in school eight hours a day.
5. Lack of opportunity to work/learn/study in mixed-age groups. I think learning in a group which has kids both slightly older and slightly younger than themselves gives kids the ability to use the older kids as inspirations and to see themselves as teachers and leaders of the younger kids, all of which is very valuable. Plus, it's more similar to real life than an environment composed entirely of same-aged peers. That never happens once you're out of high school.

So, for now, that's my list of worries. But how worried should I be...? I'm not sure yet :)