Flare needs a slight revamp

[Kenji1134]

For a level 50 job ability, Flare is extremely limited in its uses, and even when a use is found, it is very cumbersome to execute without becoming useless for a good while.

Flare's issues can be broken down as follows:
1. MP. The single most glaring issue with Flare is that it plunges your MP to 0. At that point your only options are to use Convert, once every 3 minutes, or to use Transpose, and wait for a tick of mana from UI1.

2. Cast Time. Flare has a base 4 sec cast time, making it the longest cast we have, and difficult to use in fights, even more than Thunder 3. This means that Swiftcast is the only logical option for using Flare, once a minute.

3. Power/Cast/MP Ratio. Lets compare Fire 3 to Flare. Fire 3 is 220 potency with a 3.5s cast, or 62.9 pot/sec, and costs about 1/3 of your mana pool at most.
Flare is 260 potency with a 4s cast, or 65 pot/sec, a whopping 3% more dps than Fire 3, and leaves you dry to boot.

Proposal:
Make Flare a base 5s cast, with 500 potency, with a 5y aoe range, affected by the umbral-astral buffs in the same way all other Fire spells are.
Make Flare cost 0 mana, and have a 3 minute recast, to match with Raging Strikes.

The idea is that Flare, like many other final job abilities, should feel powerful, be relatively easy to use, but not spammable.
Right now we can do (F3), Flare, Convert, S-Cast, Flare, Transpose, wait...
This gets you, ignoring Fire 3 for the AF3 buff, 520 potency over about 5 seconds, counting the minor internal gcd of ogcd abilities. And you pretty much rely on these extra abilities to make Flare remotely useful.

By changing Flare to be a 3 minute recast, we can justify making it roughly as powerful as the current "Flare Combo", but without have it leave us with 0 MP at the end, and being overly reliant on several other abilities to be useful.