Besides the fact that the newest installment in the Asterix series is a general disappointment (as obviously nearly everyone on this site seems to agree), but in my opinion one of the worst aspects is the instance of possible racism in the new book.
In former Asterix-adventures the reader was treated with loving parodies of different country's inhabitants, e.g. by exemplifying every single cliche about the British in a humurous way. Before the newest book was published some had actually hoped that Asterix and Obelix would experience Asian culture.
But what we get here is an ALIEN obviously designed to represent Asian features and going along with a complete deconstruction of the Japanese comic scene. By showing the readers that for him people from Japan are not even worth to be represented as human beings Uderzo shows that he nowadays follows a path Goscinny probably would not have approved of.
This is neither parody, nor satire, nor homage. This is not necessarily racist but inappropriate and unbelievably stupid nonsense and is just another aspect that makes you wish that Uderzo would just stop endangering the elements millions of fans around the world loved about Asterix.

Yours sincerely,
Algernon