Wow, the post limit here is really short. 1000 characters is like 7 tweets.

I do not have experience playing BLM because well, as mentioned, it doesn't have enough damage to make up for its drawbacks.
I want to play it one day, but it's currently unappealing.

But I think there's an extremely simple buff that'd bring BLM up to par: increase damage dealt while in the center square of Ley Lines by another 15%, to 30% total.
This is a 5% total average DPS increase if it's always used off CD and if BLM can stay in that square. Bit higher average DPS increase when timed with other cooldowns.
Ley Lines doesn't seem rewarding enough to me against bosses that really move you around a lot. Granted, it's very easy to stay in it against some bosses, I think that change would reward timing ley lines correctly during a phase where you can stay in it best.