I get the basics of the mechanics of that attack from looking at it. You select the move, it goes through what appears to be three phases of "charging" and then it fires for what looks like around 300K total damage to everyone you're fighting. The phases of charging the attack seem to take about 5 minutes (I'm not sure how many rounds, I didn't count... but a five minute charge for a single attack is quite a bit excessive). Then, you have a 30 second actual "firing" animation with some fairly extraneous animation that looks like it could have been cut. Do we need to see that same tower looking thing three times for the animation of bolts of energy from space hitting a target? I can't say that we do (even if I'd have context for it, I could see arguing that it's a bit excessive and extraneous for what amounts to a bunch of lasers from space satellites hitting the enemy).
Also... I'm not "comparing everything to final fantasy". I used Final Fantasy Summon animations as a reference for what I consider "overly flashy". I even used a Chrono Trigger reference for what I consider "overly flashy". I honestly have no problem with "flashy" in general. All I've said is that you can make your animations as "flashy" as you want, but at some point players will get burnt out on them. Especially if they start to take too long. By all means, make animations flashy. Just, don't expect them to hold up after the 20 hour mark or more.
But, if you want a good argument against flash in general... I present to you "Dwarf Fortress". There are very few, if any, actual animations of combat in that game (sometimes you can see breath attacks... or enemies get flung and splattered... But you don't see much beyond that). Yet, the combat system in that game (and combat in general in that game) has a huge draw. Why? Because when you read the Battle Log of what happened... Oh, it's way more interesting (and funny!) than any RPG to date. Go ahead, lets see you animate some of the random crazy stuff you can read happens in combat in Dwarf Fortress. Flash? Who needs flash when you have Dwarves biting armadillos in the leg and then punching through their brain?
Honestly, I would argue it's not really about how flashy your animations are. I'd argue it's how much fun your combat system is to engage in to begin with. Graphics are nice and all, but it doesn't take much time for them to become "dated" and "old". If you must focus on either flashy battle animations or your actual combat mechanics... I'd vote mechanics.
Don't let that deter you from making battle animations that look good or have a bit of flair... I just don't think that aspect of any game is more important than the story, the characters, combat, states, equipment, maps, items, and the skills in general. I'd say animations would be something you do when you've got the rest of that done. But, that's just me. Some people love graphics above anything else in a game. I try to avoid those people, but they do exist
