So with the blessings of Forge World I have been thinking on the units that I would take with a Scion army, with Imperial Armor filing in for some support and providing some interesting options. Having the ability to take the same FW units that the IG can helps out so much in filling some of the scion army gaps.
First off it fills the AA gap that scions have in the form of flyers. For me I'll be taking the Avenger Strike fighter, as I just love how it looks and it has solid weapons. Its not the best AA platform but can cause flyers stress, and if you can get them to jink you reduce their firepower. Vultures are another top choice for similar reasons. Both will cost you almost exactly the same when kitted out. The Sky talon is another interesting choice, if you don't use valkyries a lot for transporting squads, this gives you almost the same firepower of a valk at a discounted price. The lightning is the cheapest dedicated air fighter, but honestly I think the vulture and avenger can do the job and fill other roles better if you aren't facing any flyers. The Thunderbolt is the most reliable air killer, but most expensive. Its a solid choice and can still do well against ground targets. Its a very solid AA choice.
Other units that this now opens up in my mind that can help the scions out are salamanders, tauros, rapier batteries, cyclops, and even some of the artillery platforms. The salamanders are good, they are cheaper than tauroxes and bring good firepower, plus are fast enough to keep up with the infantry. Tauros fill the same role as well, though I like their aesthetic in the scion army better than the salamander. I would take the heavy flamer or multi laser venator upgrade.
The rapier batteries are an interesting choice as they bring needed long range anti tank weapons into the army. They are 40pts per model and can take an additional guardsman for 6pts. They have the artillery profile for T7 2Ws with 3+ save and the laser destroyer array is 36" S9 AP2 Ordnance twin linked. Three of those are pretty cheap and easy to hide, and ordnance means your having a high chance of penning armor. The Cyclops is another interesting choice. They are 30pts and act as infantry and have a controller, they act separately from the controller but if they get 48" apart the cyclops can't move. You can detonate it in your assault phase, whether it is in combat or not (it can assault). When it detonates its basically a basilisk shot ( S9 AP3 Large Blast Ordnance) place the blast marker over it and kill whats underneath. Its slower as it counts as infantry, but a unit of three of these is cheap and can shore up a flank from their simple threat of being there. Hide them out of line of sight in a ruin or other terrain on your flank and jump out when anyone gets too close.
There are hydra platforms at 50pts and manticore platforms (sky eagle) at 100pts, but personally I would take a flyer and double that as my AA. Another interesting option is tarantula sentry guns, which are super cheap at 15pts for the TL heavy bolter one and 35 for the TL lascannon. They are artillery and have T6 2Ws and 3+. You decide which mode they are in at the start of the game. Point defense lets them shoot at targets in a 90 deg arc up to 36" and sentry mode is 18" but 360 deg. They will shoot at the nearest unit based on weapon. Lascannon will shoot at nearest vehicle or MC, and heavy bolter at nearest non vehicle target in line of sight. They are really cheap and are a nice fire and forget flank cover.
For me, there are some fun little stuff that I want to play around with, especially the cyclops, prob won't be amazing but would def be a fun little to use. I'll have to do a list up and see how it works out. Then play around with it and see how it does. Hope this gives some ideas
GG