A little more complex than necessary, but pretty much.
The easiest way to reach the same conclusion is to simply look at the new recipes. They show six combat classes in six sets of gear. Since CT, both tanks, casters, and healers share the same gear. One of those sets of gear is a re-colored rogue uniform, the gear sets are ordered in threes. Three melee in the first shot, three ranged in the second shot. That's all you really need to infer that the rogue is strength based. If you want to take it further, yeah you can look at the rings the 'rogue' is wearing and you can take a look at the fact that ninja is never shown in the Coil or Shiva fights (doesn't mean much, unfortunately), but you can also infer that between the ninja, monk and dragoon one of them is going to share gear with the other in order to maintain that 1 in 6 chance of getting armor you need to drop. And the proof is in that new recipe screen.
Now obviously, those recipes for new gear probably aren't the only pieces (we have PvP gear to consider too) we're getting in the next patch. But the clincher is the fact that they showed the rogue uniform re-color as a crafter set next to historically tank/heavy armor seals it. If they had shown another piece of combat gear (assuming there is another set coming), then it would've been a bit more difficult to establish. As I said earlier, ninja have their own PvP gear with a bat-like theme and previously, physical DPS classes had their own unique sets, thus it would've seemed likely for ninja to get their own gear in end-game content.
But now that we've established that SE wants to maintain that 1-in-6 chance (thanks to the video), we can also infer that future classes - the expansion tank and healer - will end up sharing gear in late game content as well.
This also pretty much narrows down who the tank could be. =)