Found something interesting, and a bit alarming.
If you're attempting to increase the Stars on a city that already has 13 troops officially, and you've already put a large number of traits of that kingdom's troops-- for example, 28 traits completed-- then any increase by soul-levelling up ONE maxxed troop will give only TWO points of kingdom progress.
Two points! That couldn't be right...
Then I realized the problem's probably because I don't actually own the 13th troop. To put a further 6 or 7 Stars on levelled cities, I think you'd have to obtain the kingdom mythics like Pharos-Ra, or the new Jotnar Stormshield.
And yes that does mean there's a need for DRAAKULIS too