My eighteen year wait for a browser setting

Back in 1992 when I first started using the web (the internet is not the web, but that's a subject for another day) the only browser available was Mosaic. Mosaic rendered pages using black text on a grey background. There was no CSS. Typeface styles could not be set inline either. Typefaces, sizes, styles were all set in the browser and were common to all sites visited with that browser. Images were a luxury as few people had the connection speed to make them viable.

As time went on those who wrote front-end code were given more and more power and scope to make websites look any way they wanted. A good designer built a site that was not only a pleasure to look at, but easy to navigate and most importantly easy to read. Others did not. So browser developers retained the styling capabilities of their legacy systems. The one that remained most used was the text-resizing. This allowed users to retain the typeface, the colour and the style of text the designer intended but resize it for ease of reading.

Later browsers grasped the idea of the page being 'rendered' with both hands and abandoned the text re-size in favour of a whole-page zoom. As useful as this is there are still times where poor markup causes text to be hidden behind another element. No amount of zooming can alleviate this so I can still override the typeface size with browser settings.

But in eighteen years of being a regular world-wide-web user there is one feature that I would still love to have. A simple setting that I would make reading just about anything online a far more pleasurable experience. I want to control the line-height. I want to be able to increase, and in some rare instances decrease, the space between lines of text in a paragraph. Is this so hard?

And for the record I know I could probably do this with some clever custom default CSS, or something like a Greasemonkey script but I think this is a such a huge usability issue it should be built in to all modern browsers.