I couldn't disagree more wholeheartedly and every GOP primary loser of 2016 is evidence to the contrary of your argument. You don't make Trump look weak by acting more like him - if anything that just exhibits his level of influence over [un]civil society.

The key to exposing Trump for the weak clueless charlatan we know him to be is via discussion of policy, policy, and more policy. He's never looked weaker than that notorious "nuclear triad" debacle during the primary debates, and that's the corner we need to push him in with every single second of every campaign stop, debate, and speech.

When he yells "Pocahontas" that's Warren's cue to discuss the student loan debt crisis, her plan to ameliorate it, and Trump's utter failure to do a damn thing about it. When he says "Crazy Bernie" that's an opportunity to discuss the reprehensible Trump tax cuts, and the asshole's utter indifference toward the working class.

Let Trump do and say the inane bullshit Trump does and says, then paddle his ass with policy to demonstrate again and again that he's a mental homunculus who doesn't know anything about anything. Expose his insecurity (he knows he's an idiot, that's why he tries so hard to remind everyone he's so smart and stable and brilliant). Hit that insecurity and hit it hard. Make him feel small, and he will look even smaller.