Oh I have NO problem with the premise that the Kings need a new identity and they need to move on from those two at this point. That's valid and totally reasonable. It's the idea that "Kopitar isn't a good leader"/"Shouldn't be a captain" type stuff. Frankly, we have zero idea what that means in a professional hockey environment and, as KP pointed out, Kopitar has been trusted by every coach and GM he's had to be the defacto everything on this team for 15 years. If that doesn't make a good captain, I don't know what would.
You had Modano in the previous list. Dallas named Morrow captain and bumped Modano down to an "A" after a 77 point in 78 game season because Morrow signed a long-term deal and was a heart and soul type player. Like Brown, Modano still played several seasons for Dallas after the "demotion".
After winning the Cup in '99 and going back to the SCF in '00, they were swept out of the 2nd Round in '01, missed in '02, upset in the 2nd round of '03 by the Gigueres and then lost in the first round the next three seasons before making the conference finals in '08 post-captaincy change.
Dallas was a pretty legit team from mid-late 90s up through 2008. After the 2nd round sweep and two first round exits, they looked around and said it was time for a shake up because what was happening was unacceptable based on expectations.
Does this make Modano a bad captain? No. But you had a guy that had been in the league for almost twenty years so you know it is going to end so you make a change to prepare for the future and to shake things up a bit since the results weren't there.
For the Kings, the results have definitely not been there and they also don't have a Morrow-type player that they just signed to a six year extension. I think Danault fits the bill if you wanted to make a change but they probably feel like they can't pass over Doughty.
Kopitar being captain was a case of giving the C to your highest paid player while hoping the weight of the letter would propel him to greater heights. Secondary reason to maybe lighten the load on Brown so he could rebound a bit. Well, save for that Hart run, he's basically been the same guy which is a great player but still the same guy.
If you're going to do the "best player wears the C" thing and said best player isn't a killer, you need to have some killers on the team. Blake appears to have drafted next-to-zero killers and every prospect that comes in winds up assimilating into what 11/8 have set as the template for "Kings hockey" which can basically be summed up as "the power play is our enforcer" (hat tip to Andy Murray).