Well I guess it's ultimately a matter of "love it or leave it" but that said, some of those points you raise are reasons for concern.
One way of controlling some of those downsides might be to do what Myspace and some other sites out there have done:
(1) create groups and give ownership of that thread to the thread starter who can delete any inappropriate posts. This will free the admin from having to monitor each post. This also means a person who intends to post slurs, abuse and other such things realizes their posts will be deleted right away if they blatantly violate the rules. This is already practiced in some way in the blog section and it might be a great idea to have something similar in Kurakani. Each user needs to accept the rules laid down by the thread starter when they post. If they dont like those rules, then they can start their own threads.
(2) Ban users who start willfully malicious posts (personal attacks, racist, casteist comments etc). This will have to be an on-going process just like it is on so many sites out there.
(3) Take stern action against repeat offenders. There are people who are just mean and then there are people with serious mental problems posing as everything from god to godzilla putting out despicable stuff sometimes using public resources like libraries etc. Several sites have initiated action against such public institutions and ISPs who allow such people access to their resources. This site might want to do the same the ward off such behavior.
Just some suggestions in the spirit of openness.