I don't necessarily agree. I used to produce commercials and have had to give such direction. Sometimes it is necessary. The skill is knowing when to step in and I think that not only did the engineer step in too soon, he was also wrong and even said so himself.
Though the second take was certainly in the direction that the engineer was asking for and should have let it go.
I'll agree here. I've done commercial production and have also been the one behind the mic. The engineer/producer would have done better to let him finish the first take and keep his comment to a brief "Okay, that's good. Now... could we do another take, but with a little
more energy?" That should have been all that was required.
Even so, you can tell that Shatner was listening to what the guy said at the same time he was laughing at him, and had it pretty well dialed in from the start of Take 2 -- that's a pro at work. On the other hand, that "Uhhhhhm" thing the guy was doing after both takes and the tone he used weren't terribly professional and were (I suspect) what ultimately prompted Shatner to let him have it.
Did Shatner perhaps go overboard with it? Yeah, he did, a bit (it sounded a little like he was playing to an audience of one or two other people who were present in the studio) but I can kinda see what he was going for.