Or, you'll use element.classList.add()
>You'll rewrite .ajax() and .when()
XHR isn't really too verbose.
>So you'll rewrite .animate()
Or you'll do elem.style.transition = ... and use elem.addEventListener;
Really, the plain DOM isn't that bad. If you make one or two sugar methods, they'll be far, far, far smaller than jQuery, and probably far faster.
What's the point to use shims or polyfills if it means including some others libraries ?
JQuery is not slow. If you .addClass() two hundred divs, sure. But for basic DOM manipulations, it's fine.
JQuery is not heavy. 32kb. It may be in cache. You'll likely gain that twice 32kb by optimizing your png.
This anti-JQuery war is a silly fad started by people who don't make websites.
And as per arguments like "a fadein should not be mandatory blablabla", explain it to the client. It may work. Or it may not.