Adnan Syed has been proven guilty in a court of law and has exhausted his appeals to the point where this is basically his last chance. The new evidence are the revelation that cell phone data might not be 100% accurate and that of a shaky alibi from an unreliable witness. Neither one of these are the bombshell that could overturn a guilty verdict.
From what I can see, the main idea is that he murdered her because he seemed so calm by her disappearance. Yet, there are just some people like that in the world. Some things just don't phase people like they normally would to other people. I'd prefer substantial evidence before I believe he murdered her.
It is not because his story was republished in a popular podcast that the murder of "Serial" Adnan really happened. It has been blown out of proportion by the popularity of the podcast and by media attention brought more and more forward by the makers of the podcast to increase its popularity.
For me to pass judgment on Adnan for allegedly killing his girlfriend in 2000, I would have to be really informed on the topic at hand and couldn't possibly convict an innocent man without such knowledge. So even though he could've been the murderer, I could not agree with the debate question without knowing for sure.