I have been trying to be positive about every unit in the Chaos Space Marines Codex, not focussing on what it can't do but trying to focus on what it can do. However, I'm afraid that the incoming post is going to be a bit more negative. It's not that I think that this unit is the worst in the world, not at all, but I do think that it's not very good and the insistence of some of my friends that the Defiler is the definition of awesome has annoyed me to some degree. So, here we go.
In comparison to its last incarnation, the Defiler has increased in points. Now it is just shy of 200pts. So what do you get for these extra points. Well, now you get a 5++ save, 'It will not die' and Daemonforge. So essentially, it has been made more durable. But is it really worth it. I would argue that the previous Defiler was better.
The reason being that it was durable enough as it was anyway, it was a tough old thing, so adding more durability to it is on the point of overkill (or overlife). I would say that it is to such a point that the Defiler will struggle to make its points back. You are now paying almost 200pts for a Battlecannon that's going to be sticking around for a while. Are you going to kill 200pts of models with that.
Now I've also seen people argue duality, saying that the Defiler can shoot well and do combat well. But can it really do either well enough to justify it's cost? It doesn't matter how durable something is, if it can't dish out the damage you're not going to win. Now you could always just say tarpit units but at least they free up your more deadly units to do some damage, so the technically are helping doing some damage, and minimising it to your more valuable units.
So, does either the Defilers shooting or combat capabilities allow it to do enough damage to make it worth it. Let's start with combat. It has 2 Power Fists and 2 Attacks. So 3 base due to the dual combat weapons. So at most I'm going to lose 3 models a turn, and that's if you get lucky with your WS3. I'm going to use an example from my own experience, in the times of the old Chaos Codex I was playing in the Steel City Wargaming – Tournament of War (there's a post about it under tournament reports). In my last game 6 Grey Hunters tied up a defiler for about 5 player turns, ultimately winning me the game by a pretty convincing margin. The fact that it took the Defiler so long to chew through those shows that it isn't great in combat. That is half the game assuming a turn 5 ending.
So, is its shooting ability any better? Well it's BS3, fantastic, and although one big S8 power armour chewing template does look good, if you think about, you can take a better armoured alternative in the form of the Leman Russ Battle Tank through allies, which is 45pts cheaper than the Defiler. Plus, I can always use cover to at least get a save from that thing, if it uses it's longer range of 72” it's probably shooting at my Long Fangs and if I know there is an AP3 Large Blast template on the table I'm going to put them in cover, it's that straight forward.
So, let's just do a straight up comparison to the other Heavy Support choice that I've been through so far. For 15pts more, I can have 3 base Obliterators. On durability, both are really durable, a 12 armour vehicle (meh) with 4 Hull points (sweet) vs 3 T4 Ld8 models (meh) with a 2+ save and 2 wounds a piece (sweet). So how much damage do they put out, let's just assume Plasma Cannons for the Obliterators. Would you prefer to have 3 S7 AP2 blasts at BS4 or 1 S8 AP3 large blast at BS3. I know which one I'd go for.