1. Why the NHL Can Do More Expansion

While the NFL has had similar rumblings, the NHL has one distinct advantage: a larger talent pool. I know what you're thinking:
"The NFL is the largest league in North America! How can this be?"
Here's how.
Most NFL players are American, so pulling talent from a singular pool dilutes it quickly. While the NFL is making efforts to expand globally, it's still a predominately American game. The NHL can pull talent from countries such as Sweden, Finland, Russia, and Canada (of course).
Plus, the NHL has two countries they can tap into for expansion. Having both the United States and Canada gives it an advantage, with markets such as Quebec City, Houston, and Atlanta being targeted. The NFL doesn't have that yet, and their prospects of going to England are a ways away.