Homeschooling can be a great option, my eldest grandchild is being schooled at home. But it isn't for everyone.
First, you need a VERY dedicated and focused parent who knows how to educate others. Just being intelligent doesn't mean someone is a great teacher. I have been in training sessions led by some of the best and brightest in their professional fields who lost everyone in the room inside 2 minutes. Second, the parent needs to be patient and flexible. Just because they are ready to deliver a lesson doesn't mean the little kid is ready to hear it...but flexibility can be a huge plus when it comes to homeschooling. Different methods and times can be easily incorporated.
Third, things that are normally extra-curricular in traditional education are still important for a well rounded education, so the parents need to seek out groups and expose their kids to things that develop the ability to work with others (like group projects and sports do in schools). While sports are not for everyone, I think the are more valuable for kids being school at home if, for no other reason, the disciplined physical aspect they provide and the social interaction.
Fourth, everyone should have some exposure and appreciation for "the arts" and music. They need to be worked in to the education is some manner.
Bottom line...it can be excellent as long as the parent(s) don't give a half-assed effort.