I'd be tempted to go if I hadn't just been over there less than six months ago, and if the pre-ordering of tickets wasn't going to be so difficult on a foreign-language site.

The thought of a week long convention to celebrate 30 years of Transformers (which BotCon isn't doing), interests me enough to number crunch the money needed for this.
At least if I went, I'd still be a little familiar with the area, as my Hotel was near Haneda airport, which is on the Yokohama side of Tokyo, and went through Yokohama a couple times on the train.