A good topic sentence could be something like: Globalization make everyone a neighbor. If you unpack this, then you can say that globalization creates a world community that seeks to understand each other.
Another way you can go is to study international cities and how these international cities are a microcosm of globalization. I remember Mike Bloomberg, the major of New York, coming up with a brillant slogan to get the olympics to New York. He said New York is a city where everyone has a home field advantage.
HSBC also has some great advertising about globalization. They call themselves the world's local bank.
Finally, you can speak of unity in diversity and the power and greatness that this could produce.
Do you really mean "should" here? I was thinking a more likely topic would be to what extent DOES it affect us. But assuming you do mean "should" here's what my thesis would be:
Although globalization can have negative effects, it should cause us to identify with all people off the world rather than just with those from our own region or country.
From there, I would talk about how wars and other types of conflict are often caused by nationalism. When we feel that we as Americans are different from Chinese it is likely to lead to problems.
But with globalization, we have the chance to understand people from other countries much more through the internet and other media.
I'm sure there are many other opinions, and I'm not sure that what SHOULD happen WILL happen, but that's my opinion...