Well first off, I don't know why people are still proposing changes to this as there is noone actually updating this data.
That being said, I wouldn't mind moving kingler up to C rank. Yes, for the most part he is outclassed by samurott yet samurott is one of the best and diverse pokemon in the tier. Kingler also doesn't have good bulk at all. Even though Kingler has 115 base defense, its 55 HP means it will barely take physical hits better than Samurott, while having a very lower special defense. What it has going for it, however, is its initial raw attacking power that can brought up even higher with swords dance. Even though it is very frail, not many pokes will be living +2 attacks, especially because kingler has 75 base speed, which outspeeds ludicolo, seismetoad, luxray, and of course, samurott. The ability to outspeed and either kill with x-scissor or a +2 return alone justifies its use. It can be said, however, that Kingler is very predictable. What about having ice beam on it? Coming off neutral nature with no investment, sheer force and life orb, an ice beam from Kingler does about 60% of a timid 252SpA Samurott with life orb, and kingler's enhanced speed (if a +speed nature is used) could potentially get 2 ice beams off. Kingler can 2hko tangela and 2hko offensive vileplune, while having a 21% chance to kill defensive vileplume. Not exactly great, but I don't see why running an Ice beam/ crabhammer/return/ swords dance or agility set cannot work.
A better comparison for Kingler would be between floatzel and basculin. Both have aqua jet and higher speed, but less bulk and no boosting move. Kingler is definitely not an E poke, but I agree that a lower C rank could be justifiable for Kingler