1.1 General Workflow / Lockout System
The job mechanics can be split into 4 parts:
1) Aetherflow
2) DWT(Dreadwyrm Trance)
3) Bahamut
4) Rouse
1.1.1 Aetherflow
The core mechanic behind SMN is aetherflow. Without aetherflow, you are basically losing the ability to execute the majority of your other job mechanics, namely DWT and Bahamut. Therefore, it is extremely important to highlight that the no.1 priority of SMN is to attain the maximum number of aetherflow stacks. In order to achieve this, it is highly favourable to keep aetherflow on cooldown as soon as you can in most cases; the odd case being speed runs where you should have already pre-planned a kill timing. This is something that I feel some of the other rotations neglect. Although it may appear logical at first sight to fit in 3 festers and make full use of your first DWT, refreshing your aetherflow at ~20+ seconds opens up a huge possibility of you losing an aetherflow usage at the end of the fight. I will not go too much into the numbers, but it should be very clear that losing an aetherflow usage, which translate into a Tri-d, DWT and possibly even a bahamut is an overall potency loss.
So what locks out or prevent you from using aetherflow? DWT. With the new changes to SMN in 4.0, aetherflow stacks can only be gained after you have used up your dreadwyrm stacks.
1.1.2 DWT
With DWT having a duration of 16 seconds, in order to prevent ourselves from locking ourselves out from using aetherflow once it’s cooldown is up while still enjoying the full use of DWT, we have to use DWT at least 16 seconds ahead of aetherflow cooldown. Following this concept, a general rule of thumb is that you should be using your DWT when your aetherflow cooldown is at ~ 18-20 seconds.
So what locks out or prevent you from using DWT? Bahamut. In Bahamut trance, you are able to use aetherflow stacks but are unable to use DWT.
1.1.3 Bahamut
Here, we are further extending the interaction of ‘lockouts’ between DWT and aetherflow. With a duration of 20 seconds, you have to use Bahamut 20 seconds before your DWT lockout timing (i.e 20 seconds on Aetherflow CD). This brings us to our next rule of thumb, you should be using Bahamut at the very latest when aetherflow has 40 seconds left on its cooldown.
So what locks or prevents you from using Bahamut? Rouse. As Bahamut de-summons your pet, you should be trying to maximize the use of your pet abilities before using Bahamut trance.
1.1.4 Rouse
You should know the routine by now. The next rule of thumb is to use Rouse 20 seconds before Bahamut to get the maximum usage of Rouse before de-summoning your pet. This brings us to a full circle where you should be using Rouse at the very latest when your aetherflow has just finished its cooldown.