[parkher]

For me, T2 is a great reader because it is rooted and has AMR installed, so I can use Cool Reader and GoldenDict with it, and the book indexing is disabled.
So far it seems that there is no chance of this happening to T3, so therefore there is equally no chance of me buying it.

As to Aura HD - now it already has those two advantages of T2 - on Aura HD now we are using Cool Reader and also Kobo book indexing can be avoided.
The main disadvantage - so far there is no dictionary integration into Cool Reader.
There is also the screen size issue. With Aura's 6.8" screen, landscape orientation is not needed - I can have 7mm margin + 88 mm text + 7 mm margin.
7 mm margin is large enough for comfortable reading (I hate small margins).
88 mm text width is typical for mass market paperbacks - measure a few, you will see.
So Aura gives a real book impression.
With 6" screen, I cannot get 88 mm text with comfortable enough margins so I am always using landscape.
Turns out, landscape gives one big advantage: it is much more comfortable to hold the reader in your hand: you can turn the cover all the way back and the reader just hangs on your fingers and you don't have to squeeze it so it does not slip from your hand.
It just hangs on the finger(s) of a fully relaxed hand.
With Aura's portrait orientation I would need a cover which opens on top for that, so holding it in my hand is not as comfortable. There is always an increased danger of dropping it. Besides it is heavier, naturally.

As to the built-in front-light, Kobo Aura has a huge advantage over PaperWhite because it has the OFF button. So I never ever switch that light on. If I ever need a light, I clip on Ozeri Kandle Flex - when illuminated by it, the screen still looks like a page of a book, not like an LCD screen with the internal Aura's light.
And PaperWhite is glowing even on the minimum setting. Glowing e-ink, what an oxymoron! As I say - a class action suit waiting to happen.