I agree with most of those points. Her punish damage is way too weak and she feels needlessly unsafe for what she gets.
I wouldn't make Nitro 0 on block, I'd make it -4 or so. If it gets blocked, Jade isn't immediately punished, but definitely loses her turn. I'd make one or two of her strings 0 or slightly plus so she has a safe option that doesn't immediately lose her turn, but one that rewards hit confirming instead of always ending in Nitro since you know it's gonna be a coin flip on the next turn.
I'd be fine with making Nitro safe but keep the damage as it is (low risk low reward option) and leaving butterfly unsafe (maybe even more unsafe), but have it do more damage (either buff the move itself to be heavier hitter, or make it pop-up to extend a combo). That way you'd have access to damage at a proper risk/reward balance. End strings with Nitro for a safe low damage option, end strings with Butterfly for more damage, but eat shit if you don't hit.
F2 needs to be slightly faster to be a threat. 20 seems about right? Hard to pick a number. They can dial it in to a place where it is still seeable, but maybe not take an entire commercial break to land.
I've been saying since beta that her space control is overrated. It's good, but it is hardly dominant. Many (most) characters have tools that can contest her reach, so it's not like she completely shuts down anyone. And being so unsafe on everything means one wrong guess and her opponent is right next to her. I don't think you need to reinvent the wheel here, just shave a few frames off the recovery of her longer reaching moves so it takes more than one block to get in on her.
I really like Jade. I think she has some really good tools that just need a tiny bit of tweaking to feel right. Nothing crazy, just a little something to bring her more in line with the Skarlets and Sonyas of the roster.