I think he feels like he has to carry the show working with Michael Cole. Personally, I'm not too sure if he likes Cole and professionally, I'm pretty damn sure he doesn't like working with Cole.
I remember King did an interview in which he stated that he enjoyed working with Cole and it was somewhat of a nice change from working with Ross.
He went on to elaborate that he feels Ross does way too much pre-match preparation for the shows, and always made a point of meeting earlier in the day to discuss the shows. Lawler said that he and Cole are both similar in that they like to simply get to the building and pretty much go with the flow, of what comes out of their mouths as it happens. Obviously, there is some scripting, but he says he feels their broadcasts come across as more natural.
Ross even commented on that interview, and said something to the effect that he "didn't know he was being a burden on Lawler with his pre-show preparations, and that he was glad that he and Cole enjoy each other's styles." Then, he went on to wish them the best.
So I think Cole and Lawler actually enjoy working with each other, and is probably serves them a nice break from their old partners, Ross and Tazz (at the time).
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Aside from any of that, I have no doubt Lawler could go back to his old self tomorrow if he wanted to. The reason he's acted the way he has for the past several years, is because Vince McMahon tells him to act that way. Vince seemingly wants his commentators acting like real commentators of a real sport, as that is the way each of his commentating teams have acted for the past several years.
I personally think Face/Heel broadcasting teams make for the far-more entertaining broadcast. My guess is Vince will never let Lawler go full-fledged heel (given his new vision of how he thinks wrestling announcers should be), and instead will only allow Lawler to do this with one or two talents.
