King Road and Strong Style are both concepts of Baba and Inoki, it's not only style in ring, it's also booking style, pushing style, backstage policy, even arena using. You won't find Japan NWO and running Dome Show every year in AJ, for example.
There's no wrestlers as strong stylers, it can only be applied to certain company. Say to Nakamura do 30 minutes mat-work with Tanahashi - he will, he came to noah and has match with Morishima and is told to do sprint - he will. If wrestler isn't told he just does his usual offense. Kicks, high-fly offense or mat-work. Whatever.Of course there's a lot of very limited wrestlers.
King Road and Strong Style are systems, they both had evolution and had different periods. Basically SS is style of NJ, but 85 SS and 91 SS are different. Same with KR, but it came to GoGoGo style in the ring in the end. Also KR and SS are not exist outside AJ or NJ.
If we talking about SS it's came from Inoki being crazy over MMA, in ring style aspect, first it was - 95% of matwork with high speed spots (suplexes, run of the ropes) inside (see Inoki vs Fujinami), then came Choshu time (and beginning of Lariats) plus stiff kicks (see UWF). To put it simple - it came to kicks, hard chops, submissions combination. And pretty standard formula (matwork->spots) has been used. That formula was borrowed by modern Japanese indy widely by the way. Add to it gaijins, juniors and mma things and you get NJ.
KR came from technical and pretty slow paced wrestling matches of 60s and 70s, then it got speed from Choshu invasion in 80s and came to what to what we know. It used different formula of matches, if NJ match started slow with submission, in AJ it started with chops and elbow, for example, and then slowed down, but then it could have long finishing sequence with fighting spirit, lotta move etc. But original KR had more deep storyline. It's not storyline in terms like Randy Orton gives you 1 hour speech, it was storyline in match itself. Match was story. Often based on different interactions before. And there very important role was played by 3 on 3 tags, NJ never had it. 3 on 3 tags were vital part of AJ, people could get like six matches in one thanks to that. And it brought some exchanges and further builds. Then deep storyline in match had disappeared and what left was moves after moves, head dropping etc. And original KR died.
In general KR ring style focused around storyline inside, building moves, selling, stiff strikes and playing off past encounters. SS ring style focused around submission (you get match end in an instant from armbreaker), hard and power moves and much more simple formula. But as I said above it's not only in ring work, it's more how Baba and Inoki viewed wrestling.
In the end SS is pretty much style NJ uses. And KR style is not used anymore. Noah uses what called noah ark. It has something form KR, but no way it can be called KR in any form.