Honestly, I can't think of a single thing Kingmaker does better than Wrathfinder, except maybe exploration but I myself prefer a more restrictive, tighter design approach because it often makes for better pacing and plot structure. I like Serpent Isle way more than Black Gate for that reason for example. Wintersun does have the adventure-y "run into things, discover quests" thing going like BG1 and Kingmaker but let's not forget you're supposed to be leading a crusade here, not go out adventuring in the woods. I'd rather have the devs try a new approach than emulate the design of past titles and of which there are already a million other copycats. I definitely wouldn't call it decline at any rate.game by game Kingmaker was a lot better in general than Wrath
Someone tell Owlcat that chinkos don't play their game.