You picked a few bad examples. Coincounter is like the old bosses in 1.0, where you can derive everything you need to know to kill him from his body. Is he twirling his club in a circle? Swipe is coming, tank run through. Did he turn to face a non-tank? Everyone stack behind. Is he focusing super hard on his club but not moving it? Tank stun or everyone run out.
Cutter's Cry Chimera the EN client tells you everything you need to know without ever looking at his cast bar. Blue eyes? Run out. Violet eyes? Run in or way out. Orb chasing you and violet eyes? Run way out. Everything else has an AOE indicator.
Many of the mechanics in coil have an indicator other than the cast bar or can be completely avoided with positioning. The only one I can think of off the top of my head where the cast bar is your only indicator is Twisters. Maybe could argue Lunar Dynamo, but Dynamo probably won't kill you if you get tagged by it and can be avoided just by staying at melee or max range. Actually, I guess the old High Voltage in BCoB, but that only required two people in the raid to watch it. So let's see:
T1: High Voltage on ADS. All of Cad's attacks have AOE indicators or are meant to be healed (spit attack)
T2: High Voltage on ADS. Allagan Rot is what killed people, but the cast bar does nothing for that.
T3: lol
T4: Pox, I guess?
T5: Death Sentence, Twisters. Everything else had an indicator of some sort.
T6: Everything has an indicator
T7: Watchig your debuffs more important than the cast bars.
T8: Can't really speak to T8, but don't remember anything that requires watching cast bar.
T9: Dynamo and Heavensfall if you're in weird positions. And you can even save yourself from Heavensfall for many classes.
I can't really speak for FCoB, but nothing I remember seeing about them necessitates watching a cast bar. Granted, I could be remembering wrong. . .