In an attempt to make something productive out of the hyberbole you're trying to use, I do think Leylines should have a lesser effect on other casters standing in the circle. You (BLM) get 15% speed increase, WHM/SCH/SMN get a 5% increase. Casters tend to bunch together so nothing changes in groups and BLM gets some group utility.
They were bad ideas in the first place so that wouldn't really hurt anyone, but that's for another topic.And remove the cast times from WM/GB while you're at it.
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This said, the problem with Enochian is that it's a mechanic that is stand-alone. It's sort of like that kid that sits in a corner by themselves while the cool kids (Astral Fire, Umbral Ice and Thundercloud procs) just mingle with each other. I'm sure some of you are awesome at your job and can make it work, but I'm looking at it from a design perspective. What synergy exists between Enochian and the rest of BLM gameplay is sort of forced through the need for one spell (Fire IV) and little else. Even thundercloud procs fit naturally because of the gaps in the 2.0 rotation that gave you time to use it.
Sure, you're doing mad deepz under ideal conditions (I've seen good BLMs make a mob's HP bar evaporate), but I'm not a fan of the design. If BLM at 50 was a perfect three-layer cake, Enochian is sort of a 4th layer that they tried to add but keeps wobbling from side to side. It's not toppling the cake nor making it less tasty, but it just doesn't look as perfect as it did before.