Rizen
Smash Legend
I've been learning K.Rool to see what makes him tick. He's probably the best anti-projectile heavyweight, which is where my bias for him came from. Crown powers through projectiles, DA belly armors through them and his counter reflects. A reflector is a big deal, not because returned projectiles are a big part of a match but because the projectile user can't set the pace.K. Rool is a character that I think is best summed up as "remarkably ok." From playing him a lot I can say he doesn't really feel terribly awful once you really simplify how you play and base it around just....really basic fundamentals and a lot less button pressing than the rest of the cast.
He doesn't feel like the average Smash 4 low tier but I do agree he seems relatively kinda weak, but there's a lot of really weird potential I see in him. Not potential to shoot up to godlike or anything but, there's a lot to look at.
The Frame 4 jab is really nice too I can't really be dishonest about that. In general I've found that he revolves a lot around placing crown smartly and using the frame advantage it can give you when placed nicely to stick out a blunderbuss fireball or move forward. His edgeguarding is where I think he ends up being strongest because he has a really good back air (its one of those moves that works well because its vastly slower than his other aerials, meaning its an automatic timing mixup ala Cloud Fair vs Cloud Nair or the likes) and just can generally assert himself really deep offstage as long as you don't Dair too low or use Uair at all.
K.Rool seems designed around winning trades. Ftilt tanks attacks with belly armor and counters; Ftilt may be f12 but the armor's f5-11. His startup data is good and where it's not the armor comes in sooner. Like you said his edge guarding is very good. Where he suffers is if he guesses wrong he has weeks of lag. Each of his moves has a single purpose but doesn't cover multiple options well. If he attacks and you shield/dodge he's in trouble. Dthrow not leading into kill moves until late isn't a problem; he can still use other throws or Dthrow>frame freaking 5 Utilt. Basically he's a bully. He wants you to play his game but you don't have to. Fortunately he's heavy enough and has a long recovery to stick around.
K.Rool's not as good as I initially thought but far from the worst heavyweight. Kossismoss seems like the player to watch.