A lot to unpack there but to put it simply, most of your suggestions will either not change the situational nature of the spell or change it to be a mandatory spell for certain builds.

Your aqua breath change for example will turn aqua breath into another song of torment with half the duration and to that I say no thanks, keeping song of torment up full time is annoying enough and you want to add a second one that we have to upkeep twice as much? Did you ever play BRD or SMN in ARR when their DoTs had different durations? It made them a rotational nightmare, not to mention you’d have to bristle both spells each time so you’d need to be 1 GCD ahead at all times.

Flying frenzy loses out to J-kick because J-kick is oGCD and instant cast while frenzy is GCD and has a cast time, you could make it 220 potency and it won’t change that. Frenzy is a lower level spell that’s meant to be replaced by J-kick when you get it, there’s nothing wrong with that.

I agree that a lot of old BLU spells could use a rework or an update based on how BLU has evolved, but having read through your suggestions the only one I can fully get on board with is loom.