You've got to know when to use and when not to use it obviously, but it's not that unsafe. (Using it against characters with fast punishers is obviously a bad idea.) I rarely find myself punished that severely when using it outside of combos.
I've come to appreciate 4A in JS lately. It's got pretty good reach and basically leads to a free mix-up. Same with 22A, though you have to be a lot closer.
Also take advantage of her break attacks in GS, especially on wake up. If you mix them in with 66(6)B you can catch people off guard or...
Her options in Jolly aren't that bad, they just have very low damage output unless you go for unsafe follow ups. Sometimes chipping the opponent away at range with simple pokes can be more effective than trying to rush down with Gloomy.
6A is great, but it's kind of the only good ranged poke that Gloomy has and it's high. I generally prefer to stay in Gloomy, but if I find myself in a situation where I need keep my distance then Jolly seems like the better option with 22B, 6A(B), 44AA/2A, 4A, etc.
I haven't had as much trouble with Natsu as a few other characters, but it could just be I haven't fought any really good Natsu's, since she does seem to do ridiculous damage given how fast she is.
You definitely have to keep an eye on your positioning when using 66K. If I'm going to end up in a disadvantageous position I usually just use 3B, 4A, 3B/3AA instead.
I just remembered that 4A does hurt you very slightly, so you can transition into Jolly if you manage to hit the 40% life mark after using it. But that's pretty rare since the damage is so low.
I definitely prefer her english line then, because that makes no sense coming out of Tira. (Unless she's saying it sarcastically or connivingly, but even still...)
I find GS 3B, 66K to be the best non-meter option, since it does about 70 damage with no self-damage and no chance to go into Jolly. (Plus face surfing is always fun.)
I've stopped using 3AA in that combo unless it's the BE (or near a wall/ring-edge), since 3B does roughly the same damage...
It really depends on how Clean Hits factor into overall damage output of other characters and whether that was factored into the base damage of attacks with the Clean Hit property. If they decided to forgo Clean Hit attacks in favor of more consistent damage output then that's cool, but if she's...
Pretty much. Every character has certain moves that have a random chance to Clean Hit, which does more damage than usual. (Ironically you can "Clean Hit" even on whiff.)