The one thing I'm not sure about is all the Aquerbuses. At 1000 pts you're giving up so much for those 4 snipers. Your vanguard are neutered without any plasma, and your onagers not taking all the heavy cognis stubbers they can is a huge waste.
I think I originally wanted redundant sniper teams because I know that one of the lists I'm going to see in the coming weeks leans heavily on a Mek with a Kustom Force Field that I dearly want to snipe out early on. Beyond that I'm looking for attacks that deal Mortal wounds to deal with Thousand Sons, especially the Sorcerers. However, I can see the reasoning that at 1000 points doubling up is a misstep. And you're right, it is a lot of points resting on some T3 shoulders.
My concern for that list is a lack of bodies. Your nightmare scenario is for something to get in close combat with the Kastelan. They will still find it hard to kill them but they will just neutralise them for ages.
If your enemy can deep strike you need to make sure there is nowhere they can land and assault you.
Even if they can't deep strike, ita critical to provide some speedbump units that can take an assault then fall back and allow the Kastelan their double round of shooting.
I see your point. 10 Vanguard probably isn't enough, but then, I'm not sure what can be done about 60-90 boyz at this points lvl, especially if they are in Trukks that can just drive around the battlefield and attack from the sides/ rear.
I have made another version of my list that adds more bodies, and gets some plasma on the table to synergize with the Techpriest Dominus. Due to points considerations, I added the Dragoon who would act as a "tackler", moving quickly to a melee theat, charging it, hopefully doing some damage, and tying up the threat in a round of combat/ fallback. I'd much rather have the Icarus Onager though.
Ya know, the more I look at bat reps the more I'm seeing Electro Priests as a must have for us now.
Keep them out of sight then use them to counter charge and mop up any survivors, between either the big hitting power of the Disco Sticks or the MASSED DICE of the Zappy Hands they cover a wide range of uses for us now that the Skitarii are a little lacking.
Man, I'm seeing that too, especially for the Fulgurite Electro-Priests. Having a pack of 20 or so screening the Kastelan/ Onager line seems like a good move, and Omnissiah willing, we get a quick-moving transport to carry them to battle then I think they would fill the role of Berzerkers in our army, which would be a fine thing indeed.