Thanks again for the report, sounds like a good game

Shame about the poor dice rolls in those assaults!
People have different styles of play but to me the Scions list taken looks a bit unoptimal competitively. Hope I can offer a few comments/suggestions? Chaplains are excellent in assault units but not worth it everywhere. Most people generally recommend 3-4 activations per 1,000 points played in EpicA so 15-20 would be the ideal range at 5k and 12 activations rather low. Warhounds are much better taken as singletons rather than a pack and spending 350 points on a Scout formation is excessive and better spent elsewhere. Thunderbolts are 175 in the Tournament Pack by the way, not 150.
You are doing defensive AA attacks for the aircraft yeah? Hopefully so, but thought I'd make sure. Thunderhawks should have at least 1 AA5+ attack at Stormtalons from any angle before the Stormtalons get to attack but I can't seem to see a BM next to the Stormtalons in the photos. Aircraft take a BM if they come under fire (any amount of times) during their approach move and another BM if they got shot on their disengage.
Have you considered taking Sword Brethren Terminators? With CC2+ and a character upgrade they would on average get 3.3 normal hits and 4.2 MW hits, which would have made a mess of enemy infantry or Land Raiders. You could either teleport them or the formation can be transported in 2 Land Raider Crusaders due to their larger transport capacity (making moble Terminators viable without being too expensive like regular ones needing 4 LRs are). With no titans in the list it's otherwise lacking in MW.
Sword Brethren in a Landing Craft could be good, consider planetfalling it in perhaps as you'd then get to attack 3 formations that turn rather than 1 and you'd avoid any AA. Drop Pods with Sword Brethren could be good too – they lack shooting normally, but would get the Deathwind attacks. After drop podding in SMs are slow and can struggle to get range to engage but the Sword Brthren would have more chance with their 30cm move.
I will potentially consider upping the Thunderhawk Transporter to FF5+ but I don't think it needs it myself (and I'd probably want to up the cost slightly if it did get changed) and I'd like to see it tested a fair bit more at it's current stats first. The THTs background focuses them very much on being transports and it's not really fitting for them to go launching assaults on their own, which would be more tempting with higher FF. I also wanted to have more FF hits be an advantage of the Landing Craft. At present 3 THTs cost the same as it but have 2 more 4+ reinforced DC and can't be wiped out by an unlucky critical, so they need disadvantages in comparison.
The table at the end is wrong by the way (says Scions had 0 victory condition when they had 2).