It would be kind of neat if they had a generic list of universal "chapter tactics" that everyone could pick from for their faction keyword. They'd have to be abilities that anyone could feasibly use, though I guess it'd be hard to make abilities that would be useful for everyone. You could even mine the old Warlord traits if you're feeling lazy. It'd just be a simple table that everyone once picks from.

Examples (off the top of my head):
-FNP (6+) equivalent for <infantry>
-All characters re-roll one dice to hit in challenges
-<jump> and <jet> infantry trigger mortal wounds on HoW on a 5+ instead of a 6+
-+3" range to ranged weapons
-One unit in the army improves its AP by 1
-All <vehicles> gain IWND (6+)

These were off the top of my head, so they admittedly suck but you get the idea.

You could even just do like the Imperial Militia and Cults list, and give players the option to pay for army-wide upgrades/abilities based on the faction keyword. That would be reaaaaallly cool (if probably hard to balance) because it would give options to make any army play differently for a price.