Ooooo break it down! I'll dish my take on this subject

Risk: Risk involves more than just maybe not getting something, it also involves losing. Call me casual, but I feel kinda crummy playing for hours and feeling like I've gotten nothing out of it. Imagine feeling like you've gotten done Less-than-nothing. So if you're going to risk something the reward has got to be worth it. That's why I'm not too thrilled with these rumors going around about weakening the rewards of multiple melds on materia... If I'm going to blow 100s of mils of gil, I want to have the reward that goes along with it please. Now if we dumb down the reward we need to dumb down the risk as well. Gotta keep that in balance....

Reward: Rewards can be anything gil, materia, mats, exp, CGI cutscenes, any sort of happy progress is a reward. Rewards need to scale with risk and difficulty or else you won't feel it. That's why the level up graphic needs to be flashy. If I'm grinding all the way to max level, Id better see fireworks, strobe lights and like a red carpeted choir singing my praises in the tune of the FF fanfare when I get there.

Probability: When I see probability, I just think meh... time sink. Whatever it is, you're going to end up doing it more than once so you'd better get real comfortable. You're gonna be there for a while. I don't really have a problem with this, but it tends to be the best stuff that has the lowest probability. In 1.0 there was no way to really improve probability on ANYTHING. So you had to speedrun spam stuff so you could increase your probability by sheer number of runs. I hope we get to change this in ARR somehow. To give us at least the illusion of some sort of progress. Token systems allow you to progress outside of RNG, but I think we'll still be speed running dungeons at some point in ARR, the mechanic is just too convenient.

Difficulty: Here's where it gets dicey. Difficult battles, difficult dungeons, difficult puzzles are necessary for some people. Its not about hardcore or casual, but some people actually enjoy losing 100x before a win. It makes that win sweet for them, gives them community cred, and the satisfaction and memories are long lasting. Its that lovely pay out. But then you have to contend with the people who don't have the patience or skill to lose 100x but they STILL want that same drop or loot or whatever. SE, if you want to put up some difficult stuff, and make the drops and pay out worth it, be prepared to deal with some consistent, persistent, never ending belly aching. And the rest of the community will have to deal with it too.