Honestly, I feel as though manual control over kerning will become an anti-pattern for most designers.

Most good OpenType fonts have kerning data built in, and its pretty simple to enable this feature for most modern browsers (Safari is lagging, see font-feature-settings). There certainly are times when you want to override the default kerning, but its few and far between, and certainly not a good idea for body copy.

I'd rather have improper kerning for old browsers, and nice kerning for new browsers than trust designers to properly manually adjust the kerning themselves.