1.She doesn't have any great mixups. Literally everyone I've played online got used to them after a couple of matches and easily punished. Just block low and then high, rinse and repeat.
2.Nobody respects them after a while cause she just doesn't have good pressure up close. Most characters have faster pokes to get out.
3.Haven't worked on this too much tbf. I haven't found a way for her bombs to work really so I use the other variation.
4.Again her pressure is non-existent and easy to get out of and punish. People say you can do some chip or throw but that's my problem. With other characters I find it so much easier to get on a roll and mixup/pressure/get some decent damage. With Frost I struggle way to much to keep up and I've labbed with her the most out of the roster.
Also I strongly disagree that she's terrifying in the corner. Aside from getting a couple more S1s before ending a combo when my opponent is in the air, she's just able to land a bit more damage than midscreen which is true for every other character.
In general my main issue with her is how hard it is to punish people with her normals' range or how slow the longer range ones are. 12 and 34 barely hit any blocked moves. She doesn't need a whole set of new tools, just a few tweaks on the ones she already has.
All in all I agree on a lot of OP's points.
Let me counter counter point you.
1. She doesn't have safe 50/50's if that's what you are referring to. But most characters in MK11 do not either. Her mixups comes from her stagger pressure/throw/D4 poking game. If you are fully committing to full unsafe strings (B32D1) and not hit confirming, you deserve to be punished. Hell, B32 is safe....start doing it naked and start tacking on blade spin. Both options are safe, and if you want to get real cute, meter burn the blade spin (also safe and it lasts an eternity) you are going to have opponents questioning when to hit buttons. That's off of one string. Start trying to do B2~bomb drop and B22 and see how they are reacting. If they are respecting the bomb, keep doing more pressure. If they aren't blow up what they are doing to get out of it.
2. You need to start using her range. D4 can literally be blocked, and beat out another characters D1. If they start trying to down 4 you back, do a slight walk back and bring out the b2. She has great neutral.
3.Her bombs work as a tool to get opponents to DO something. Either they will block it, get hit by it, or try to avoid them. Watch what they do and see if you have an option to beat it. For instance, if you are doing D4 and do a random close bomb buffered into it and they respect it, there's pressure. If they jump as soon as you throw your head, punish it with D2 or F2 (jump back etc) she has options based on what those bombs make her opponents do.
4. She isn't a super combo heavy character. Yes Sonya and Scorp etc are going to get more off of their confirms, but they also can't dictate space QUITE like she can. Her pressure once again, is based around staggers and range and her safety of frames.
5. The corner point was spoken by Kindred earlier, but she doesn't give a shit about wakeup attacks. She has a safe hit confirmable way to check them. Once they respect this, back up and throw a bomb at their feet. Start short hopping, throwing B3 staggering B2 staggering etc.
She isn't an MKX character, and she definitely isn't Cyber Sub Zero. If she was, she would be broken as fuck in this game. The only point I will honestly concede at this point is her punishing options. It was painfully clear picking her up she had consistency issues...in BOTH variations.
EDIT - Her bombs can be blown up, and that's by design. You can't be too predictable with them. If you use her second variation and play someone who just neutral crouches from 3 quarters of the screen and can omit her entire offense, you will see why I consider variation 1 her best atm.