I'd been interested in both of those but I haven't found anything about Frayed Knights (guess I should try the demo) and I keep hearing that KotC is only good for the combat.
Yes, KotC is very combat-heavy, the story is simple and nothing special (but not bad either) and while the game offers enough free exploration, there aren't many sidequests, so in a way it's a bit sandbox and
linear. If you're looking for very story-oriented RPGs, this might not be the one. It's still a good game though. The demo gives a good idea about the gameplay, even if I think the combat in the demo is a bit harder than most of the combats in the actual game are, and the game offers more exploration, too.
I've read it's good but brief. Unfortunately, "brief" isn't very descriptive. I beat the storyline part of the demo in an hour-ish though I've heard that people have spent upwards of 50 hours exploring the demo.
I wouldn't mind playing a short RPG as long as the few hours I'd spend with it are fun. I'll try the demo, thanks!