The black in Black mage stand practicly for the dark art of destruction. Whe use esspecialy strong magic to hurt people. What is called the "black art".
The lost of sharpcast bothers me not so much (even, when it was sometimes fun to use).

But i agree with the thunder spell. It looks weird, to have it bond on the phases (maybe you could say, that the thunder is a by product that comes, when you switch between the 2 phases).
I like the animation of the new fire spell. I only complain, that it is again a explosion. I want some variation, like a beam or fire wall. Simply a line (aoe) attack. Instand of allways round aoes.
ANd the potency is lower, as i had imaged it. But, it was stated by a yter, that it has the fire buff to, and would be, with 10 potency, stronger, as Despair.

And yeah. Its true, that i practicly wanted to be a pure fire mage and was a little disapointed, that i was forced to use ice spells at the start (practicly, what i wanted would have been the non-standard, who i practicly doesnt knowed yet).
But i must agree, that the BLM is focused to much on fire spells now.
Whe had a new strong fire/ice spell in EW. Now was practicly the time, for having a strong Thunder spell for between or as a finisher. Or, even a ice spell who hit very hard, after you prepared 3 Umbral souls and ice shards (like, having it 700 potency, who is even stronger as Xenoglosie). And bring so balance to phases.