There was a rumor at one point that they might broadcast the four biggest WWE pay-per-views live for free on the WWE Network. If they actually did that, it'd be a huge selling point. They are currently trying to make something like $50 bucks a pop off those, so a lot of people who like wrestling and watch the no-additional-charge shows on USA Network and SyFy every week (or even just occasionally) can't afford these PPVs (or aren't willing to get majorly ripped-off to pay for them). There are a lot of economically lower-class people who love their wrestling, so it could be really big for a lot of people if it opened up events like Wrestlemania, Summerslam, the Royal Rumble to normal cable/satellite non-ppv tv.
Having said that, I'd be surprised if that rumor actually comes to fruition. WWE makes a lot of money on those PPVs and won't likely want to give that up. A WWE Network channel without any of their bigger fresh weekly and monthly programming -- PPVs, their two big weekly shows (Smackdown and Raw) -- isn't nearly as attractive, even to wrestling fans. It'd be left with third-tier weekly stuff like WWE Superstars that even die-hard wrestling fans don't usually watch, plus maybe highlights or reruns of old wrestling programming, which is available in other places.
So, to me, a lot of this depends on what programming is actually on the channel. If they put on live broadcasts of big events like Wrestlemania that are currently PPV, which I don't do, it'd be almost must-have. If they're just broadcasting Superstars and reruns of old stuff, it'd be something I might flip to occasionally, but wouldn't really care much about and wouldn't miss much if it wasn't there, to be honest. It's going to depend whether they want this to be a major "must have" kind of product that might hurt their short-term revenue, or whether it's just some extra junk they want to make a buck on without really providing much value.