I never got this impression... but that is an interesting thing to read into.
This is, of course, sort of a matter of reading the tea leaves, aka we may see what we wish to see and not what is real.
However, there are some signs of it. Mearls had a prominent role with the early official adventures for 4e, that was AIUI the part of 4e where his work was more prominent than other authors, whereas for other books his role was more minor. And those adventures...are not very good by 4e rules! They're slow and grindy with a ton of unnecessary combats that only exist to cause slow attrition (something 4e is...different about vs other editions), the mechanics of the fights are largely dull, and the skill challenges are some of the worst examples in the whole game. In general, the Pyramid of Shadows and the Keep on the Shadowfell are both regarded as really, really bad--and dealt a terrible blow to early adopters who figured that must be what 4e would always be like. So that's strike one.
Two, we already knew there was a problem inside WotC, of designers constantly (but not strictly intentionally) making Wizards more powerful than other classes. Heinsoo didn't name names about this, saying it was a team issue that he had to repeatedly correct for. But it's not hard to think Mearls just subconsciously thinks (or thought) that Wizards are better than other classes in D&D. And then, when he was put in charge...we got Essentials, which very specifically produced some of the weakest, most poorly-designed classes in the game, like the Binder. Yet the Wizard was almost untouched by this, getting several perfectly solid options. (I say "almost" because the Bladesinger was bad. Getting Wizard
encounter powers as
daily powers? Uh...no.) That's strike two.
And then, as noted, Mearls made openly anti-4e edition war jokes during a podcast. Very specifically, he used the "shouting hands back on" joke to make fun of the idea of a Warlord that heals people, as part of talking about why they weren't going to make a Warlord class. He followed this up by saying "I'm being ridiculous," but it was a really noticeable example of the hostility toward 4e ideas, not just mechanics but the very
concepts 4e used, coming straight from the top. It's notable that he never used any other edition-warring rhetoric, and was in fact very respectful toward old-school editions. For me, that was strike three.
Mearls just...either he never grokked 4e and the reasons people liked it, or he outright disliked it, or he thought he was making things better when he was not doing so. Regardless of the reason, he was clearly unenthusiastic at best regarding 4e and frequently opposed to its concepts and structures. Crawford seems to have a much more open mind, and seems to value rules consistency and clarity much more than Mearls did (probably from many years of doing Sage Advice.) So I look forward to seeing how this change of leadership affects 4e's legacy.