Alright here's my two cents
First of all, don't even get hockey involved in this argument. On ESPN's list of the top 50 most DIFFICULT sports to play (they took into effect hand-eye coordination, stamina, agility, power, size, etc... basically every aspect of any sport), Hockey was NUMBER 2, behind Boxing.
A simple explanation to WHY soccer players dive is because of the lack of scoring opportunities in soccer. Soccer/football/whatever you want to call it is a game of glory moments and one goal games. A high score in soccer would be 4 to 1, as opposed to hockey or lacrosse or various other sports where scores can reach double digits. This is partly why people find soccer boring to watch (I beg to differ). That being said, a successful dive can result in a penalty, which, hopefully, can result in a goal. Soccer players will do ANYTHING for that tiny advantage. It doesn't matter if there was no contact, if it could possibly lead to a goal and a win, they'll dive and face the criticism for it. Sports like hockey and football don't need dives because a hockey goal or a touchdown is nowhere NEAR as rare as a soccer goal.
Next, personally I believe that Soccer is more difficult than Football. Football is rougher (obviously), but Soccer is the most mentally draining sport I have ever experienced. EVERY second you are on the field you HAVE to be thinking. On top of that, position is huge in soccer, moreso than in hockey, lacrosse, or baseball (three sports I've played as well). Soccer gets physical, and oftentimes have I seen kids split their heads open going up for headers in the crease, and soccer also requires extreme technicality and agility with and without the ball at your feet. You'll never truly understand the difficulty of some plays unless you play the sport, and let me tell you, everything that professional soccer players do has massive thinking behind it, and hours and hours of practice to back it up. Football has numerous plays, and each player runs their part in them. Soccer has no plays, everything is on the fly. Of course, certain objectives exist when attacking and defending, but each is subject to change if the unexpected happens, and most of the time, it does.
And to the guy who said hitting a baseball is the hardest thing to do, I agree, but that has practically nothing to do with the rest of the argument. I think Soccer is more difficult than Baseball personally, but then again Hockey is by far the most difficult in my opinion. I'm not Canadian either haha.