I have a problem with two plot points that aren't rilly unresolved but rather just bug me.
1) The fact that Conan can't tell Ran who he is.
I know that this is to protect her, however if the Black Organization were to try to kill Conan that would mean that they found out who he is and they would kill Ran anyway.
2) Why Shinchi had to take the pill in London.
I'm glad that this happened, but if the translation that I read was correct Ran asked the people if they had seen a Japanese boy. Wouldn't Conan fit that discription as well? If it were me I would tell here that the proffesor and I changed location, and I was in the phone booth to call her and tell here that, and later I would push the live brodcast from London that Conan alredy thought of.