T2 change that you offered would be nice but not essential. I disagree with the change you suggested to Enchian regarding procs. I disagree with the change to B4, that just isn't needed, as with number 5 because the drop to our DPS would be significant and would make us even more noncompetitive.

My suggestions:
Astral Fire Duration Increase
Thunder 4 - Thundercloud giving extended Enochian by 5 seconds (so that using Thundercloud doesn't punish you)
Allow finish of B4/T4/F4 cast if the cast has started even if Enochian drops off
Fix of the F3-Gap-F4 bug.
Reduction of the Mana cost of F1 to be the same as F4 (so that using F1 instead of F4 doesn't double punish you)
Enochian skill always fully refreshes Enochian (so only B4 is a diminishing return)

Then give one of the SMN skills a small magic vulnerablity debuff so they have more utility.

What the above will do is bring QoL to BLM, and make casters able to be a viable option in raids where there aren't any "cheese" mechanics that force the use of a caster - and allow caster heavy parties to compete with Melee heavy parties.