This system is still going to be abused. There is nothing you can do about it.
I'd almost argue that in a way, it could be worse. At least with karma, you could only +/- someone max once per day.
Unless you guys have blocked this, then there is nothing to stop people liking 10 of their friends posts, and pushing up their respect by 2.
I cannot believe something as petty as karma has come to this. It was just meant to be fun, and people take it so seriously, that it requires a minor overhaul of the site. This time could have been spent improving the site for much more useful purposes including reintroducing the news board, which could be used to announce the new essay topics are available for the essay writing initiative, give important dates such as UMAT rego cut offs etc. The admission test board has still not gone ahead. There are threads discussing LSAT, SAT, GAMSAT, UMAT etc. I think it is time it was introduced.
Also, I remember the CTO saying that a 1.2 forum upgrade (I think) needs to be done. It seems a fair amount of time has gone into this new 'Respect' system which I would consider a low priority.
I would have just eliminated negative karma to avoid potential arguments and left it at that. Also, with no more karma, you could get more 'spam' posts as people can no longer post quick 1 liners to each other.
Oh well, what is done is done. I agree with Cianyx on this one. I don't think the site is much better off. Although the anonymity of the post 'dislikes' is a good way to avoid disagreements.
Considering you have gone this far, I would suggest you keep the ability to rate posts, because I actually like the idea as it gives an indication to forum users about the quality of an individual post, but remove respect or karma or whatever you are going to call it all together. I believe 'Respect' is not a great name for it either because it sounds somewhat serious, and creates this perception of a hierarchy.
This will stop people abusing the system. You can roughly tell from post counts how much people have contributed to the site, to me that is enough.
Edit: And I also suggest you create the ability for users to select whether or not their post is available for rating, because some people will not appreciate it when their essay or study score or whatever is disliked.