I'd say the WJC is definitely overhyped by the broadcasters such as TSN, but it doesn't change the fact that it is quite an exciting tournament and that I'm looking forward to it every single year.
The reasons why it's exciting is first and foremost because the featured players have not been hit by fame and money just yet, and are therefore leaving their heart on the ice. It's hard to imagine a 30 year old NHL player from Slovakia, being paid 5 million a year, leaving his heart on the ice whilst playing for the Carolina Hurricanes (not any player in particular, just an example). They are also full of energy and the speed is incredible, and as someone said, it is hard to go back to regular NHL games after watching the WJCs for a couple weeks.
Nonetheless, most players at the WJC will never see the NHL or will only have extremely short stints in this very same league. Sometimes, even the best players from a certain edition don't live up to their expectations, and I have dozens of examples just off the top of my head.
TSN is without a doubt giving this tournament an importance that it does not deserve, without me taking anything away from it.