After several years, more than a decade in fact, working with the UN, sometimes for the UN, I came to the conclusion that UN will never have military capacity for the following reasons:
- contributing states want to make money and loose 0 combattants,
- nobody is accountable to anyone for doing or ot his job,
- Troops contributing countries do not have modern armies. And when they have one, they keep it home because they busy fighting a modern conflict (like Pakistan and India for exemple)

It is not a question of understanding or not the local context, the regional context, the political context or even the international context. It is not because they have no intel, no contacts with parties of the conflict, no military capacity (well sometimes it's the problem too)... In few words, it is not because the machine design on paper is not capable.

UN are able to address modern conflict... On paper.