Air instant blocking actually was taken out in CS1, it was a CT-specific defensive feature. It made sense due to the fact that if you bursted at all during the round, you lost your barrier. If air IB didn't defend from AUB attacks, jumping would have been certain death. With the revamping of the defensive system in CS1, air IB defending against AUB attacks while shaving off 10 frames of blockstun would just be too much. The barrier gauge no longer affects your burst, it's a fair trade and good decision.
I'm not LK, but personally I think neither is more "useful" than the other. Wake-up gold burst is much more viable though for characters without a normal reversal or if you don't want to take the risk of having your dp blocked/baited. However it still costs you your get-out-of-jail card that you may need to escape a game-winning combo or to keep yourself from losing a large amount of life and being put in a bad position. Green is not as "good" as Gold burst since it'd be rather unfair to get out of a combo for free and get one yourself. It's the consequence for using it to escape damage.
I wouldn't say Hazama isn't doing well, or that Chariot crew is over-rated. The qualifiers have been very rough, lots of top players showing up and competing at the same qualifier. They wind up knocking each other out.
Don't use B+C to tech. In CS2 I think it's a lot safer and smarter to use A+B (together, don't mash) along with your desired tech direction to increase your chances of defending against air unblockable resets.