I honestly feel silly wishing for buffs on SCH... LOL, but I agree Dissipation is one of those horribly niche skills that's just sitting there looking longingly at you from your hotbar. I like your suggestion, but also think it kinda defeats the original purpose of the skill, so I'm not surprised it got patched out.
Honestly, though, to make it more worthwhile, I think Dissipation should reset the CD timers on all fairy skills. It's way more powerful -perhaps concerningly so,- but at least the 30 secs without Lilly plus the massive MP cost and loss of Swiftcast would more or less be worth it to get two super WDs or two Fey Winds in a one minute span. Still situational, but now much more in line with the rest of SCH's tactical toolkit.