On the surface Ghazi don't look that threatening because almost all of their weapons have a range of up to around 8" to 10" (the size of your zone of control or the large teardrop template). However what Ghazi do offer is an incredible amount of variety, and a tool for most jobs.
The jammer is a particularly feared weapon because it doesn't require line of sight to fire. This means your 5 point Ghazi is very happy attacking extremely expensive heavy infantry from the safety of total cover, without having to worry about any AROs that could be deadly.
Jammers are technical weapons which means they're fired with WIP instead of BS. You'll notice that the WIP of a Ghazi is 15, which means it shoots the jammer with a higher accuracy than most PanO troops have with their guns. If you win the face to face then the opponent has to make a BTS save against damage 13 or be isolated, which means that troop cannot receive any orders from the order pool except its own. The jammer isn't lethal, which is a downside, but it is a weapon you can use whilst running all over the board and firing safely from behind walls! Want to brick a 100 point TAG without them firing back at you? Go for it!
I cannot stress enough how important the Jammer is for Ghazi - there are very, very few offensive options in the entire game that can target opposing troops without line of fire. The Ghazi has one of those options, and it hits on 15s.
The chain rifle and e/marat are both large direct-template weapons (so they autohit if the opponent fails to dodge). The chain rifle is a damage 13 hit against ARM. The e/marat is a damage 13 hit against BTS, which it halves, but isn't lethal - it isolates the target, and also immobilizes them too if they're heavy infantry, a remote, or a TAG. The combo of these two weapons is powerful because you can always pick the one that exploits your opponent's weakness - whether that's a low ARM or BTS value. They also don't require a BS roll to fire so it means that if your opponent wants to shoot back instead of dodging they guarantee you hit.
The pistol isn't the most reliable weapon when you want to take down opposing troops but it's worth mentioning here because when the enemy is dodging it's often more effective than the chain rifle in situations where you want the enemy dead rather than just isolated. It also gives you some reach out to about 16" before it becomes ineffective.
Smoke grenades are a significant piece of defensive tech that allow a Ghazi (and most importantly, other more important troops) to move around the board without provoking AROs, or to stop opponents shooting you in their active turn. The exception to this rule is obviously if the opponent is using troops with MSV2.
The jammer is also a phenomenal ARO weapon because, as I highlighted above, it doesn't require line of sight to the target to fire. So a Ghazi in the middle of the board but behind a wall will be able to take nasty AROs against all opposing infantry that enter its zone of control. However beware of troops with stealth that can move through your zone of control without provoking AROs, and troops with Veteran1 or Morat who are immune to the jammer's effects!
Ghazi also have Dogged and Religious Troop so they're pretty good at taking a hit and standing their ground too!
- Together with a Djanbazan you can pull off the classic smoke + MSV2 trick. Opponents without Sixth Sense L2 or MSV2 can only shoot back through your smoke with a -6 penalty.
- Make sure to force your opponent to make bad decisions when you attack with your Ghazi. If they declare dodge then attack with the jammer which requires a reset, or the pistol if Isolating that model isn't enough. If they declare reset then attack with the chain rifle which requires a dodge. Your opponent can never make the right ARO choice!
- The jammer isolates. Remember that isolating shuts off all comms equipment (bye, bye hackers!), and it puts your opponent into loss of lieutenant if you hit their lieutenant. An isolated troop also drops out of linkteams immediately! The jammer is capable of all kinds of shenanigans.
- The jammer has intuitive attack, which means you can target camouflage markers that are outside of your line of sight and hit on 15s. This is an amazing way to reveal camouflage markers that are lurking near to your frontline.
- If you have a Ghazi in a good position that has taken a hit consider going unconscious instead of Dogged. Why? Well Dogged means you die at the end of the turn, whereas if you go unconscious you may be able to be revived with a doctor! Choosing between Dogged or unconscious is quite important here.
As much as people complain about the power of Ghazi, they're not without counters. They can't do anything at all against troops with MSV2 that fire at them from over 24". MSV2 sees through smoke grenades, and being 24" away means they can't shoot their pistol either. In fact just about any troop that's outside of 16" can threaten a Ghazi effectively because the pistol falls off significantly, leaving the Ghazi stuck dodging or using smoke. Finally, shock ammunition, as always, cancels their ability to go Dogged.
It's absolutely true that Ghazi are ferocious troops at close range, but at longer ranges they're reasonably easy to remove. The real problem is that they're so cheap your opponent will probably have a lot of other troops you need to deal with as well, so it can feel quite miserable having to spend orders killing Ghazi.
It's a running joke in the Haqqislam community that Ghazi fit into any list and make it better. It's probably not false. They're 5 points, they're one of the only sources of smoke that Haqqislam has access to, and they're surprisingly lethal. They don't require any other support from additional troops to be effective either. However, if you do want to pair them with something then they work well with Djanbazans for the smoke and MSV2 trick. In addition to this, if you want your Ghazi to rampage through enemy lines you may want a doctor with a Nasmat remote that's capable of quickly pushing upfield and reviving any fallen Ghazi.
Bear in mind that Ghazi are extremely impetuous so they will push 4" forward towards the nearest enemy troop at the beginning of your turn, unless you spend a regular order to cancel the impetuous order for the turn. This means that if you want to deploy a Ghazi safely it's often a good idea to put them in a position where they'll still be behind cover even after moving 4". A Ghazi that's stuck out in the open is often a dead Ghazi.
If you're running delicate midfield troops that want to push up early on (Zhayedan, or Muyibs for example) then it's a good idea to set up your Ghazi nearby in order to provide smoke cover.
Active Turn Role
Different people play Ghazi in very different ways.
Some like to take full advantage of the fact that they come with both an impetuous order and an irregular order by pushing them up constantly in the active turn and really using them as an aggressive hunter unit that closes into short range and then causes all kinds of problems for the opponent. In this role the key is to force the opponent to make poor choices as discussed in the tricks section above and to try to gain maximum efficacy from your templates by targeting clusters of enemy troops.
Other people like to only use Ghazi as smoke throwers in the active turn and keep them in a rear position where they're more protected and provide more defensive, ARO cover. In this role you want to be in a position where you can act as a buffer, protecting your main force, such as on the flanks. If your Ghazi is in a more defensive position you might also want to think about using the jammer to reveal camouflage markers that get dangerously close to your other troops.
Remember smoke grenades have speculative fire so it's possible to have a Ghazi create smoke cover in your active turn without them even exposing themselves to harm.
Ghazi are amazing at AROing. A Ghazi set up in a small room or covering a narrow corridor can be an absolute ARO nightmare for your opponent. Make use of the short range templates to force your opponent to decide between trying to dodge or shooting back, and also try to use the jammer for attacks without line of sight so the opponent can't retaliate! If a link team is approaching try to knock out the link leader with a jammer attack, or hit all 3-5 of them with a single chain rifle! Ghazi are kings/queens of small area denial. Your opponent should be scared to move just about any troop within a 10" circular zone around your Ghazi!
If the opponent has overwhelming firepower then a good smoke grenade can halt a lot of aggression and protect the rest of your troops.