The OHL had a bevy of decent prospects this year ... it's no surprise, as most years they produce a ton of talent. It's a great league for players of every position ... the QMJHL is traditionally a softer league and it plays a little more wide open. The WHL offers the closest style to the NHL; where the best teams are always the best coached, strongest two-way groups. I think in terms of talent, the OHL is probably a stronger producer of top end guys because there's more rink time than the WHL. Less travel means more time on the ice, and the WHL travel schedule can be downright brutal. If anyone wonders why the Prince George Cougars are perennially terrible and don't produce many NHL names, look at where they are on a map. In Quebec, guys aren't forced to learn defensive coverages and strategies as much because the game is played more wide open.
It's not that way every year, but each league has developed a persona. The WHL was the top producer of overall NHL talent for a number of years; but many of those guys weren't the top end guys. More meat and potatoes, Robyn Regehr type guys. Now you're seeing some more top end guys coming from the 'dub (Sam Reinhart, Leon Draisaitl), but less of the middle round guys. I honestly don't know what to attribute that to.