> Wish there was another standard that could co-exist side by side on the web, something simple enough to be implemented reliably by the browser vendors.

That standard exists. It's called flexbox. It was designed to solve exactly this problem (among many others), and does.

That said, as I never tire of mentioning, vertical centering was a part of the design of CSS 2.1. The technique is called "absolute centering". See CSS 2.1 10.6.4 [1]: "If both 'margin-top' and 'margin-bottom' are 'auto', solve the equation under the extra constraint that the two margins get equal values."

[1]: http://www.w3.org/TR/CSS21/visudet.html#abs-non-replaced-hei...