Looking over the rules, it's actually a pretty in-depth ruleset, customized to each faction. 2 things stand out to me, having read through the DE rules:
1. Because of how the rout test rules work, shooting, a very high model count is VERY beneficial.
2. A fully decked out dracon could be a CC monster. Example:
Dracon w/ Ghostplate Armour, Soul Trap, Axe of Agony, Gloom Field, Clone Field, and modified biology (106) = 5 S4 AP2 attacks on the charge, auto-cancelling up to 3 attacks, stealth and shrouded against shooting, and a 4+ FnP from turn 3 onward.(6+/5+ on turns 1/2).
I'm sort of on the fence about taking melee in this format, as they did make some effort and changes to make melee good, but they also strengthened things that already hurt our things like wyches badly, such as the extended flamer rules that cause models to burn in subseqent turns. We're seriously hurt as a faction in a game system where they encourage lots of cover and all-infantry armies for a couple reasons. First off, we have no access to flamer weapons other than on 25 point medusaes. Second, they tied combat resolution results to a mechanic that we simply have no access to. You can get a +1 modifier to combat resolution if you have a "standard" or "banner", but such things are only available to imperium forces and chaos forces. It's as if the person who wrote these rules doesn't play many xenos armies.
With the battle honours system that's in place in campaigns, a seriously decked out leader character like the dracon might be interesting to use, but I expect the most successful type of leader would be just using the cheapest models you can put on the table, that are effective at the greatest range. So, for us, that would be warriors. The way the rules are written, the leaders like dracons count as both a trueborn and a warrior, so they make upgrades purchasable more frequently for those models. The modified biology rule is also extremely useful for it's price. I'd try to take advantage of both of these things. Something like this:Leader
Dracon w/ Ghostplate Armour, gloom shield, and modified biology 56Core
8 Kabalite Warriors 64Special
2 Kabalite Trueborn 22
3 Kabalite Trueborn w/Modified Biology & Dark Lances 108 (Placed next to dracon for 2+ cover save sniper nest) 108
As I put this list together, I kept noticing how tempting it was to take something like a splinter cannon on kabalite warriors, and I kept having to reverse my decision because it's so points inefficient. Pretty much none of the upgrades are worth it on warriors because of how cheap more warriors are.
The trueborn are only worth upgrading because they get access to modified biology, and can therefore benefit from the gloom field for a 2+ cover save, then get up to a 4+ FnP for failed cover saves.
If you end up playing a full, long campaign instead of just a few games with this system or something, it may be worth putting lances on warriors to take advantage of the "groups" rule, where you can spend 5 RP to increase up to 5 models BS by +1.
.....you know, I've gone through some of the other factions stuff on here too, and the balance on some things is terrible. Like, whatever fanboy wrote the "Deathwatch" faction rules paid no attention to balance whatsoever. You can get a leader in terminator armour with S4/T4 and a power sword for 36 points, while we'd have to spend 100 points to have a decent CC leader, and even then we wouldn't have a 2+ armour save.
Their version of imperial guards can take 61 models at 250 points....
...but the single most OP thing I was able to find for this game mode was to have a shadowseer with a phase field and the cleansing flame psychic power. Since each model is considered it's own independent unit, cleansing flame would hit every single model within range with 2d6 S5 AP4 ignores cover, soul blaze autohits.