I had no special difficulty leveling as SCH (I've also leveled AST and am nearly 70 on WHM as well), but I do understand the frustration. SCH is more harshly punished either for mistakes or for being paired with a bad tank who bites off a lot and doesn't rotate cooldowns appropriately.
Perhaps this was intentional, but the difference between WHM/AST's ability to sustain high HPS vs. that of SCH is more pronounced than before. I'm guessing that many SCHs are becoming frustrated in part because tanks who both pull excessively and perform poorly are creating prolonged crisis situations that exhaust the SCH's cooldowns and resources at an unmanageable rate.
AST is somewhat prone to this as well depending partly on luck of the Draw, but Noct AST shields are so powerful, especially combined with on-demand Benefic II, that they have a better shot at keeping a bad tank afloat even if all of their tricks have been temporarily expended.
If a SCH is pressed to the point of using Dissipation as a panic button, you know they are praying for a respite soon after, because they've probably already blown every CD they own (including Indom and Swiftcast) if they're so desperate as to risk dismissing the faerie.
TL;DR: It's not that SCH can't be successful or do these things, but the margin for error (for both the SCH and the tank) is less forgiving.
