I believe that topicality is a voting issue. Its main function is to fairly divide ground between the affirmative and negative in order to produce quality debate. I have never been a real fan of the Kritik. However, I do believe that some Ks are really disads with impacts that are something other than lives or nuclear war. As such, I believe they should demonstrate clear links to the affirmative, and some kind of alternative to the paradigm utilized by the affirmative.
Rebuttals are crucial.
I have seen many debates this year where the last two rebuttalists try to do too much and end up doing nothing very well. Focus the debate and evaluate the arguments made by both sides. The bibliographic tour of the constructives is interesting but completely ineffective in my mind. Don't forget to compare impacts and implications as well. The debates on this topic have become so interrelated that it is sometimes difficult to assess how the various arguments interact.