@HugMafia You can already block or report players. Its easy.

During the game: click on the players avatar. Down pops a menu with several options. Click on block or report, depending on what you want to do. After the game: go to the statistics page. click on the icon next to the players avatar that you want (block, report)

Done!

The same happens to me. I have never quit a game but my Karma just went from 4 - 2 stars after completing an excruciatingly long game. Is there a way to have the karma corrected?

this game is way to slow to depend on others to finish most of the games and to be honest there is little they can do to fix that. IF the players are playing reasonably fast then the game is going to take a couple hours or is there is lag in payers moves it could take days. most just get tired of waiting