I can't think of any reasons right offhand why having reciprocal links on your home page would be any worse than having one-way external links on your home page from an SEO point of view. There's a view espoused in some quarters that there's something "harmful" about reciprocal links in general, but that has not been my experience nor that of others here.
I think it's probably a mix up of the theory that reciprocal links carry less weight than non-reciprocal (which may be, but has not been conclusively proven AFAIK) and the idea that extensive linking out to "bad neighborhood" sites can cause problems for your site (which does seem to be true).
Maybe some day, reciprocal links will be bad, but we're not there yet. It may be that reciprocal links get less value than one-way inbound links, but they still carry value. So links that point to your home page, whether reciprocal or not, help boost the link popularity of that page to some degree, which is a good thing.
MHO, putting outbound links on your home page is not a particularly good idea in general, but it has nothing to do with SEO -- rather, it's a matter of not providing people who land on your page any encouragement to click off to another site. If the only links on the home page go to internal pages of your own site, that tends to encourage visitors to, well, click through to interior pages of the site.
Which is supposed to be the purpose of a home page in most cases.
I don't see anything wrong with reciprocal links -- I'd just rather put the outgoing link on an interior page, maybe one that's particularly relevant to the subject matter of the reciprocating site (not just some massive "links page" with a collection of unrelated links scattered willy-nilly all over the place).