xiAo-Shin Star eh idk, I mean if that's what the majority wants then I'd be fine with it. I just don't like making such hard rules that breaks immersion/realism.
It's the same thing for attacks, instead of the 50% rule I'd much prefer just hammer bottom feeders with buffs/penalties. If a big kingdom wanted to feed a little one, I don't inherently have a problem with that - maybe if we want to discourage some perceived negative behavior around that as an issue I would rather do something like an "aid tax", call it loss from beaurocratic waste/kickbacks/inneficiency/theft, so if KS difference is 100% then maybe aid gets cut -25%, KS difference of 200% gets -50%% of aid cut.
I wouldn't want to nerf aid too much with this idea, because the whole idea is the person needs help so they're probably naturally smaller than the people they're getting help from... People like to do black market trading too, I wouldn't want to ruin that ( maybe we need to dev a new feature for an actual marketplace lol).