The only problem is that most of the people who still use IE6 are in locked-down corporate environments where they can't upgrade their browsers. They most likely won't be able to install this plugin either.
You have to wonder if Google have got some sort of killer app they want to launch but IE is the problem — the sort of killer app that corporates and institutions will want access too.
I don't see that they did this to raise anti IE feeling (unless they get off on preaching to the choir).
Don't see that WAVE necessarily fits the bill but it does need proper HTML5 support ...
The only problem is that most of the people who still use IE6 are in locked-down corporate environments where they can't upgrade their browsers. They most likely won't be able to install this plugin either.