A few things to note: while the original material suggested that "THQ Australia" were working on the game, the official announcement says that Dawn of War and Company of Heroes developers Relic are behind it. Strange. Also, while the original title was clearly an action game, this one has really upped the number of on-screen enemies (as you can see in the clip below), in line with its apparent shift in genre from brawler to action-RPG.
If you'd like to know anything else about the game, tough: as with IGN's other pre-E3 "exclusives", the announcement consists of an announcement then a whole bunch of "this developer isn't disclosing this information at this time", so we'll have to wait until next week to learn more/anything.
UPDATE 1- A post on Relic's boards says that this title is not the same game that was leaked in that video from last year. That clip was "for an action title Studio Aus was working on. This is a totally different project, though it does share the same name as the leaked video used."
Sounds like the action game in development at THQ Australia may have been binned, then shifted to Relic and cannibalised for parts. We'll look into it, see if the action game is still being worked on or not.
UPDATE 2 - Yup. Sources have told us that the original action title was cancelled, but that THQ thought some parts were worth salvaging, and handed the leftovers over to Relic to turn into this action RPG.