ELI5 What is wrong with SMN?

[paradigmfellow]

I saw that list, but 4 of them are basically complaints that SMN 4.0 d....

One is that if you die, you are SEVERELY punished than most other classes (tie with DRG). Your stacks restart, including Bahamut stacks.
There is a lot of cooldown management. You have to plan it out with the fight and if you do not execute with perfect accuracy, then you will end up being the last dps.
Pet reaction is worse in Stormblood than in HW.
Bahamut has ghosting issues. The game will not register a damage with 2 seconds left in the gauge. Even though there was a hit.
If you move while Bahamut is out and do attacks, Bahamut will not attack and will follow you instead.
In order to get 11 or 12 actions from Bahamut, you have to use Addelle during Bahamut, instead of using it for proper mitigation.
Devotion effing sucks, planning for someone to get devotion will result in a dps loss and even just using it can lead to a dps loss because you could have used another attack.
Bane sucks, there is almost no reason to use it and instead, you should use painflare.
Atherflow can not be used while in Dreadwyrm trance.