I agree with the op. While the fights can be fun, it is ultimately frustrating to get to second coil and hit a brick wall because of players that do not understand the mechanics of a fight. And while the general solution to that is typically "Kick that guy and find someone else", it seems to me that's a great way to diminish the player base by excluding others. If the game were more rewarding for skill of using your job correctly and not so much mechanic heavy, so many people probably wouldn't leave. T6 for example, if you have a member that doesn't quite understand that breaking the vines come before doing damage or how to position themselves to not be devoured that can hold back the party.

They can be the best in the world at doing damage as a black mage/summoner/bard/dragoon/monk but if they don't understand the movements then they will never progress. Honestly, it's a cheap way to reward thrills and effort. Not saying mechanics should go away altogether but they shouldn't be as important as they are now.