I am going to conced that Double-cast actually has merit as a skill. Not much merit, but there is an interesting idea there. Also, it can't work on Assize since that's an ability, not spell. If it was an oGCD Lily ability that duplicated your last healing cast (not that that much healing is actually necessary in most content) and stored it for later, that could lead to some interesting ideas, kinda like SAMs double Midare button.

Everything else though is a hot mess.