This post completely misses the point of BLM. BLM's identity is "Turret DPS", and this post is written with a failure to recognise this identity.
Not enjoying the job because of the timer is perfectly fine, but it in no way kills the job. Every other BLM player can make the timer work with their playstyle. The fact that you can't just highlights the subjectivity in this post. Additionally, it's natural to have difficulty with a job's mechanics when you aren't as experienced with it. It's easy to just complain about the job if you're having difficulty coming to terms with the mechanics, but if you're committed to the job you should practice maintaining the timer. If BLM players can maintain it in God Kefka, I don't see how you can't maintain it in Shisui. It's just a lack of experience.
Once again, these changes just miss the point of BLM. I'll once again reinforce that BLM's identity is "Turret DPS". The current Ley Lines is such a fantastic skill that accentuates this playstyle. It rewards people knowing the fight well and planning out it's usage. Removing it just ruins a layer of skill from a job that has already been heavily trimmed down since HW.
The second change, I don't understand well. Are you suggesting you lose a stack every 3 seconds instead of losing all stacks after 12 seconds? That would 100% kill the job.
It literally is top DPS. This is just misinformed.
BLM does fit into the game. Naturally, a job that wants to stand still will be challenged to overcome mechanics, but using that logic to say it doesn't fit into the game is like saying melee DPS don't fit into the game because they sometimes have to go far away from the boss to do mechanics .
At the time of writing this, your BLM is level 65. That means you don't even have Triplecast yet. BLM is given plenty of tools to keep up their rotation during mechanics, these tools such as Aetherial Manipulation, Triplecast, Manawall, Between the Lines, Swiftcast, Thundercloud and Firestarter procs. If you're having trouble keeping up the rotation, then perhaps look into how you can better use these skills to your advantage, but don't try and change the class' identity to one that's more convenient for you. I think in this case, it's just a matter of BLM being a class that you aren't experienced enough with, or a class that simply doesn't suit your playstyle.