Inequality, both domestic and international, because of insufficient protections against exploitation. I say this is well worth the price.
For some countries the loss of domestic industry, which has benefited developing nations immensely (including mine), but I am of the opinion that the paramount interests that policies and resources of a nation should serve are that of its citizens.
Environmental degradation
Imperative need for stronger international authorities, like the UN, which will be difficult even on a theoretical level.
Globalisation is established under a set of rules when many nations didn’t even exist yet, but under international law, are bound to its rules by default.
Every organization strives to achieve its targets and its structure only facilitates this. The main purpose of such a structure is to help the organization work towards its goals. It brings members of the organization together and demarcates functions between them.