I think it's good that they're severing MP regeneration from the server tick because I never liked that there was a level of optimization that I couldn't reach without installing a UI addon (and also didn't like that having a high enough spellspeed could give me umbral cycles so short under leylines that it was possible for me to fail to get back to 10000 even after casting Paradox and B4).

In general, one of the things I've always loved about BLM is that every single one of its spells has a place and some circumstance in which it's rewarding to cast. This has been not quiiiite true in some expansions (like B1 is basically for if you've managed to drop out of astral with 0MP left and need to get back into gear as soon as possible, and is otherwise useless) but if at all possible I want all of the spells on my bar to have utility and not be booby prizes that a good player avoids casting if at all possible. So, I'm glad to hear that we'll need to specifically land a certain number of ice spells per umbral cycle to fully reload for our astral cycle; they have cool animations, aesthetically/narratively balance out our fire spells, and generally deserve better than being a punishment for poor play or bad luck.

The dynamicism and variability of BLM come from the interaction of its buff timers and long cast times; even if there's one optimal rotation, there's a million optimal-under-bossfight-conditions lines that players need to concoct on the spot in response to the random and evolving conditions of an actual encounter. I expect that element of BLM gameplay is going to remain even if we need to land X number of ice spells before swapping back to fire mode and even if Thundercloud is no longer randomized or whatever they're doing with it. My hope is that the 6-point fireball bar is something that can maintain its charges even if you drop out of astral without spending it, but even if not, I'm glad to both be free of the vagaries of the mana tick and to have a reason to cast ice spells that isn't just having time to kill and nothing better to do.