After submitted my site for long time (more than 6 months) many of them not approve and also not reject my site, I think this is unfair for me to leave the reciprocal links to them, so in this case how long should I wait before remove their links from my site.
A.S.A.P - at once! Why give them a free one-way link, they haven't reciprocated. This is why I don't do much in the way of link swapping, it's normally a very bad deal indeed. I no way would ever link swap with a G directory. The Golden rules is this: if they haven't returned your link within 3 days, remove them and move on. I wouldn't bother following up, as if they haven't linked back, no email will get them to respond. To be honest, really only webmasters do link swaps these days, directories are known to drop recip links, and proper businesses won't let out valuable web space to a directory for free - no chance!
if your content is worth something, when you will reach good search rankings visitors should link naturally to your site if they don't then your content is useless.
Look, if they can't respond in 3 days then it can't be that important to them right or it's not exactly a priority with them. Don't forget that you're not the only one approaching them, so they'll need a bit of time to go through their requests. 3 days is pretty reasonable, any longer without a reply and it probably won't happen anyway.
Er, I think you are greatly over-valuing the G directory model here. Good content is helpful, but other websites generally link for and prefer the traffic you can send em - that's why most link. Directories are even more difficult to get links for, because of their very nature as link hoarders, their seen as fee extraction tools that rarely deliver and thus few seek them out for searches, advertising space or anything really. With directories, you need the correct content - not mass content. I've never known any of my later directories get a huge surge of links and even less so for one-ways - never! In my early days of directory work, I got thousands of links eg: 40K worth, but honestly, most were worthless and of the low PR level. Directories are taken advantage of big time!
supercops how could you define only better ones if they dont accepts sites with PR=n/a are you going to build links with other methods ?
Ofcourse, but there's no other choice to do that. Building links will just get harder, and more sites won't do it. Why swap links for zero profit, when you can sell links and make a bundle.
it's usually the more the better, but it depends on how much time you are willing to spend submitting to directories, too many will get you bored eventually.
your point is ligit but how about no money in hand bloggers who have to get traffic + Pr they have to work really very hard and link from every single source they get for free