I have noticed a few things.
First of all your commander has both the cyclic ion blaster and the air-bursting frag projector. I ran this suit myself on a Shas'
el up until just recently. It doesn't seem to be as effective as one may think but it does a good job against hordes. The shield drones are also fine but I have a big problem with the bodyguard unit. You should also make your commander a Shas'
el not an O. If you want to keep the ballistic skill 5 then get a targeting array, it will save you 15 points. You could keep the O but unless you plan on assaulting or being in assault with your commander you are essentially paying 15 points for 1 point of leadership. That is up to you.
The commander is kitted against hordes and with the bodyguard kitted for anti-
meq and light transport you'll just about always find you'll be using the wrong guns for the job. It seems that you are using the bodyguard for their access to additional war gear and while that can be alright, marker drones are horrendously expensive for what they do. I think you would be better served by taking out the marker drones and target arrays, switching the bodyguard to a regular squad of suits and add a third member.
This will give you virtually the same amount of firepower at
BS 3 as you had at
BS 5 (including the marker drone hit) but with more wounds and save you 38 points. That will allow you to make your pathfinder squad full strength to allow two squads to fully make use of the pathfinders by making them each
BS 5 when firing at the same unit.
Your Devilfish are alright there is a bit you could do but first. If you do end up getting the 2 extra pathfinders (I highly recommend it) then you should split them into two squads. As you are already using two Devilfish the only differences are that your fire warriors cannot start inside the Devilfishes but you can now fire the two halves of the pathfinders at separate targets and can set them up separately to make them harder to kill. You would also have two positional relays in your army so if you ever intend to deep strike you can gain the re-rolling benefits in more areas along with having more Devilfish that your opponent would have to destroy to get rid of all your relays.
I should edit in a comment about the devilfishes multi-trackers and targeting arrays.
Your Stealth Suits targeting arrays do not increase their efficiency. 4 Stealth Suits are the same points as 3 with targeting arrays and will get the same number of kills on average against all targets. The only differences are that Stealth Suits with the targeting arrays have less models so have a smaller footprint, they also have less wounds so are less survivable when they are shot and the Stealth Suits without targeting arrays benefit more from Markerlights as you can boost the
BS of a unit more when it starts from 3 rather than 4. If the squad with targeting arrays has the Pathfinders mark their target then they will likely waste Markerlight hits unless another unit fires at the same target to use the extra(s).
That being said I recommend the larger squad without targeting arrays over the current one.
Personally though, I would remove the entire squad. Stealth Suits are effective harassment units but aren't as effective as some other options such as Crisis Suits.
It looks like you are going to use your Fire Warrior squads as 60 point upgrades to make your Devilfishes scoring. Fire Warriors in transports can be quite effective at objective grabbing but for the 120 points you are using for your stealth suits you could make each of your Fire Warrior squads to 12 members. They have the same efficiency as the Stealth Suits outside of 12 inches but come with many benefits but the two main ones are. They can rapid fire, this doubles the efficiency of the squad and your bulked up squads can now leave your transports with far less fear of one of your scoring units being wiped out. This means that fish of fury is now a much more viable tactic.
This is really up to you. The Stealth Suits are fairly effective but need 6 turns of firing to make up their points against basic Marines and 4 against Guardsmen while the Fire Warriors can make up their points in half that number by rapid firing. It is tricky but the larger squads allow you to use your original Fire Warriors as well with less fear. If you find that the Fire Warriors cannot accomplish 1/2 the number of turns rapid firing as the Stealth suits would (it can be hard), and you find the harassment benefits of the Stealth Suits outweigh the other benifits of larger Fire Warrior squads then keep the Stealth Suits.
The hammerheads seem to be your only anti-tank that can deal with Armour 13+. Relying on Hammerheads for anti-tank is not wise. It would take you 4.5 turns to kill 1
AV 14 target with both Hammerheads firing at it at
BS 4. 3.6 turns with Markerlights but that would involve using half your Pathfinders for this for half the game. Hammerheads are effective troop killers, especially when their burst cannons are in range. They are poor at killing tanks well. You should swap out at least one of your Hammerheads for some heavier anti-tank. Broadsides lack anti-infantry but are over twice as effective against tanks in general and Fusion Blaster
TL-Flamer crisis suits are 5 times as effective when within 6 inches, they use Markerkights more effectively for the same reasons as the Stealth Suits above and because they are so much more effective when they fire. Piranhas with Fusion Blasters are just over 1.5 times the cost of Fusion Blaster Suits but come with drones are more survivable reliable and can block the opponents forces with their wide fronts. I suggest you invest in at least one of these types of forces as you expand your army.
The Firestorm Crisis Suits can be very effective against horde armies and add to your anti-light tank. I think they would be a good addition to your army. They are also more efficient than Stealth Suits with the same number of shots per point but with 2 out of 5 of those with 36 inch range and strength 7
AP 4.
Two last things. One, i suggest you either run your Cyclic ion/Airbursting commander as a monat or change him to be the same as the rest of the members of a squad and place him there. You should keep the shield drones though. And secondly, I noticed that some of your point values were off. The Crisis command team is just the two body guards, upgrades and 2 Marker drones correct? If so it should be 214 not 266 points. The Hammerheads should also be 175 not 190 points each if I'm not mistaken. That would bring your army's total points to 1251. I should check soon to be sure.
Edit #1 if you take all the advice above the army list would be
hq 1 Shas'
el : Airbursting Frag, multi-tracker, Cyclic ion Blaster, Targeting Array, 2 shield drones : 130 points
elites 3 Crisis Suits : Multi-Tracker, Plasma Rifle, Missile Pods : 186 points
troops 12 Fire Warriors : no upgrades : 120 points
troops 12 Fire Warriors : no upgrades : 120 points
fast attack 4 Pathfinders : Devilfish with Multi-Tracker, Flechettes, Disruption Pod, Targeting Array : 158 points
fast attack 4 Pathfinders : Devilfish with Multi-Tracker, Flechettes, Disruption Pod, Targeting Array : 158 points
heavy support Hammerhead : Railgun, Disruption Pod, Burst Cannons, Multi-Tracker, built in Array : 165 points
heavy support 2 Broadsides : Advanced Stabilization System : 160 points (example of generic anti-tank)
total :1197 points
This list would definitely require more Anti-Tank. If you are working with all the units you have then you can keep the second Hammerhead and swap the Stealth Suits back in take out a crisis suit and make the pathfinders one squad of 6 again but I wouldn't reccomend going back to the origonal configurations. Better to have a more effective list at lower points

then a less effective one at higher points.
More should come soon.