Two things that I find ( in my opinion ) unpleasant :
1. Source code is hard to read ( some strange indentation and a lot of empty lines )
2. Support for dynamic content will do a lot of repaints.
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.
You've got it backwards. Never trust a font to provide your kerning, always adjust. Proper kerning is a fundamental tenant of good typography. Designers have always and will always manually adjust kerning.
