Every year the arguments about traveling to Uman for Rosh Hashana repeat themselves. I have finally heard a new argument, and it is a bit shocking.

In an interview with Rav Yoel Bin Nun on the topic, he talks about how people should not got o Uman and Rav Nachman's neshama is not there and in Uman there is only tumah. When asked about the fact that people go there and get a spiritual high, he responded that people got a spiritual high from the Golden Calf as well - and until today we still suffer from that sin. The tumah creates a powerful atmosphere and the neshama of Rebbe Nachman is crying over the mistake of people going to Uman instead of to his neshama in Eretz Yisrael
source: Ynet 

comparing going to Uman to the sin of the Golden Calf is pretty harsh. It also gives the trip far more importance than it probably deserves