1. I have no comments on whether or whether not the new up air is a better move than the old one. What I will state is that the old up air was one of Black Mage's best options for racking up damage. A move that dealt 10% (did not ever go below that) that is easily chainable with itself is a very good move. I will not deny that the new up air has potential. However, Black Mage has had his damage racking options nerfed as a result. Yes, he has downthrow. Black Mage should never be able to actually run up to someone and grab them. His run speed is awful and his grab range does not make it any easier. The character needs a reliable way of racking up damage and I don't feel like downthrow is a fun or engaging way of solving that problem.

2. Back throw is a non-issue. Forward throw does its job better while making it easier to edgeguard with thunders (both uncharged and fully charged). Back throw's usability at lower percents is a good thing as Black Mage did not lose his kill throw.

3. Down throw is always the better option due to the online nature of SSF2. Actually, I lied; upthrow would probably be good against DK and Bowser due to their size and how easy they are to combo with up air / up tilt. Everything else is just a waste of effort. I'm sure it would be a fun game to play if I could actually rely on my opponent's connection, but it's just too much of a risk to use. This sounds really pessimistic, but I really mean well. I'm always going to try to use upthrow on non-laggy persons to have more fun, but you should be able to recognize that in laggy matches, it would be a much worse option. Perhaps the people in this server may use it, but I don't feel like the vast majority of Black Mage players are going to want to spend the effort. This opens up a whole new debate on whether you think that the balance changes should be made in favour of the more competitive community or the sort of "Casual-competitive" community. Still thinking about this one actually, let me know what you all think.

4. Yes, Haste is a very good move. Come on, everyone knows that its a good move -- no one was denying it. At the very least, they were saying that its use is very different compared to his old side b. Like you were saying, this move is very good and I would suggest taking advantage of being able to recover after using it. Use haste on recovering opponents, it's very good and the risks have been reduced greatly.

5. In 9B, I liked to use meteors to apply pressure on my opponents from a distance -- especially on flat stages. The meteors would occupy a fair amount of space on the screen and would be even deadlier when they hit surface. This was by no means spammable; you would get punished greatly if you did this against characters with reflectors like MegaMan. However, what it did provide was Black Mage with an option against characters who had no problems with walling him out (Marth with spaced fairs, Samus with missles, Bomberman with bombs). It was by no means a broken option, but it would provide a very slow character like Black Mage the authority he needed in these matchups. This was taken away from him in exchange for his side b. I did mention above that I liked his side b, but it is much worse for the situations i'm referring to. It is incredibly obvious to your opponent that you are going to side b in beta. You may have been a sitting duck when doing meteors in 9B, but you would be able to cancel the meteor relatively fast and hit them with a LAGLESS forward air or side b if they were rushing you down too carelessly. My solution would be to provide Black Mage with lagless forward airs in Beta. Having another option when facing your opponent would give Black Mage the necessary mixups he needs to provide pressure from a distance.

6. I totally recognize that not every aerial should be given the same landing lag. It would be very scary to have Bowser be able to cancel his Fair animation with the amount of hitstun provided by the move. Here's what I propose for the aerials in terms of landing lag

Forward Air - Revert back to 9B
Up Air - Revert back to 9B (It's no longer the annoying hitbox it used to be. I could accept the landing lag changes if it stayed the way it did in 9B (I would not like it though!) Lowering the landing lag makes combos like uthrow -> uair more appealing and lessens reliance on 21% dmg dthrows)
Neutral Air - Undecided (I feel like there may be some problems with neutral air chaining. What do you guys think?)
Back Air - Keep Beta landing lag (I thought about it and it really doesn't deserve to have low landing lag. It's more of a KO aerial anyways [Its use as a combo move is more in relation to uthrow -> bair -> bair and is not affected by landing lag.] I think if the landing lag were lowered, it would be possible to bair and grab your opponent. I do not know how to feel about this truthfully)
Down Aerial - No opinions

7. Forward Smash being a kill move is a mistake. I don't actually mind because I play the character, but I can recognize how anti-fun this move is. It's now a move that you just throw out and it will probably KO your opponent (if not, he will be edgeguarded easily by another Fsmash at the ledge.). There's gotta be a better way to make a more... engaging kill move. I don't have an answer at the moment though.

8. I can see the analogy you're trying to go with in regards to SSF2 Black Mage being like Final Fantasy Black Mage. You use fire for the ice enemies and you use careful side b spacing for Marths (something like that). You should be able to recognize that even in the Final Fantasy world characters like Fox are the best. Have you ever played Final Fantasy 12? It is undeniable better to have your three party members use melee weapons and spam attack rather than having dedicated mages (All types of mages are foregone in favour of weaker spells, but more damage). The characters with strong moves for every MU (Naruto Nair, Fox Nair, etc.) are always going to be better than the "I got a spell for every type of enemy" ones. There's no reason why Black Mage can't have a reliable move to use in neutral like these guys. I think a lagless forward air would give him the necessary spacing option ESPECIALLY with the ability to fade back with aerials without being too polarizing (It's a decent commitment due to it not being disjointed)

9. Come on Drarky, don't stop there. Don't just give me the tip! I want the whole masamune!