Looking at the Sisters Weapons, I think the only option they have that could dent a Flyer is the Exorcist Missile Launcher. The problem is that you would be only able to hit with it on a 6, due to snap shots. If you roll for a high yeild of missiles, you could luck out and score a hit, and have a 50% chance of glancing, and 33% chance of a penetrating hit (assuming AV12). Same applies to Monstrous Flying Creatures, but they may be easier to wound due to S vs T.
That's true, but the randomness of the weapon and the need to have 6's to hit makes that a little unreliable at best. Plus, there will be plenty of other targets that they'll also want to shoot at.
If you manage to get either kind of flyer on the ground (or your opponent needs to land it), your best bet is to pummel it with as many high strength guns you have in range. Flying MCs have(had?) a chance to get back in the air, but Vehicle Flyers iirc becoming turrets, or at least fast skimmers (someone with a rulebook to hand correct me if I'm wrong).
The issue there is requiring the opponent to make a particular action. Not to mention that not all Flyers have hover mode (I believe).
If you can find a way to add Infantry Missile Launchers with Flakk Missiles, they'll give you more chances to take down flyers, whilst also providing Frag and Krak missiles.
That probably seems like the best option, but I don't currently have any current edition codexes except for Adeptus Sororitas, Inquisition, and Officio Assassinorum, so I'm unsure what's available out there to any given army.
EDIT: Since I didn't want to double post, I've edited this in.
Thinking about it, I'm probably asking too much to include the Inquisition here right now. Especially with my substandard choices. So I'm going to table those ideas for the moment.
I've come up with a new version of the army list. I like how it looks but I'm also willing to change it if I've made mistakes (again).
Primary Detachment: Combined Arms DetachmentHQ: Uriah Jacobus (
100) (Warlord)
HQ: Saint Celestine (
135)
HQ: Priest w/Litanies of Faith (
40)
Elites: Repentia Squad (Mistress + 9 Repentia) (
155)
Troops: Battle Sister Squad (15 models) w/2 Storm Bolters, Simulacrum Imperialis, and Veteran Sister Superior w/Melta Bombs and Power Maul (
230)
Troops: Battle Sister Squad (15 models) w/2 Storm Bolters, Simulacrum Imperialis, and Veteran Sister Superior w/Melta Bombs and Power Maul (
230)
Troops: Battle Sister Squad (5 models) w/2 Meltaguns (
80)
Transport: Immolator w/Twin-Linked Multi-Meltas and Dozer Blade (
65)
Troops: Battle Sister Squad (5 models) w/2 Meltaguns (
80)
Transport: Immolator w/Twin-Linked Multi-Meltas and Dozer Blade (
65)
Fast Attack: Seraphim Squad (10 models) w/2 x Two Hand Flamers, and Seraphim Superior w/Power Maul and Melta Bombs (
200)
Fast Attack: Seraphim Squad (10 models) w/2 x Two Hand Flamers, and Seraphim Superior w/Power Maul and Melta Bombs (
200)
Heavy Support: 2 Penitent Engines (
160)
Heavy Support: Exorcist w/Dozer Blade (
130)
Heavy Support: Exorcist w/Dozer Blade (
130)
Total:
2000Jacobus will go with one of the foot-slogging big Sisters squads and the Priest will go in the other (more for the boosts than for his attacks). These two will run up the centre of the board supported by the Repentia and the Penitent Engines. Meanwhile, the two Immolator squads and the two Seraphim squads will race up and try and flank/attack weak spots/generally be a nuisance in their deployment zone. The Exorcists are my only real long range firepower and will have to try and fulfil multiple roles.
How's this? Am I missing anything obvious or making any other significant mistakes?