Sorry to say but there is absolutely no way my S7 Edge will ever replace my Galaxy Tab S2.
Maybe if i am on the go and i am worried about losing it, but if i am on the couch, or relaxing on my bed, or even walking my dog, i do that on my tablet.
You did not understand a major point I made
Talking about tablets like its a universal category is like talking about dogs as a universal category. Jack Russell Terriers are very different dogs than Great Danes, just like 7 and 8" tablets are different categories than 9.7", 10" , and 12" tablets.
The 7" and 8" tablets are being cannibalized by better and better phablet sales (when I am defining tablet with current generation naming, phablets are 6" or larger phones, they used to be smaller phones, but now adays phablets are 6" or bigger). Now "mainstream phones" that are android size are 5.0" to 5.5", your S7 Edge is a 5.5" phone.
A 4x3 ratio 9.7" tablet is a much different category than a 16x10 ratio 7" tablet that you see in things like the 2013 nexus, but also the really really cheap windows tablets for $99 to $199. For screen comparison sake look at this link for an image size comparison
http://www.displaywars.com/7-inch-16x10-vs-9,7-inch-4x3
In the link you will see that the 9.7" 4x3 tablet (that is what your Tab S2 screen size is) is more than double the size of screen than the 7.0" 16x10 tablet that things like the nexus 7, and the really cheap windows tablets are.
Now visually compare a 7" tablet vs a 6" phablet with this link
http://www.displaywars.com/7-inch-16x10-vs-6-inch-16x10
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Now what will one day cannibalize your 9.7" tablet are more and more convertibile windows and android tablets. They have already captures the large screen tablet market which was 11.6" and bigger. That said 9.7" and 10.1" are in an area that is too much in the middle, too far away from the 11.6" and bigger convertibles, and too far away from the 6" phablets that this market for tablets will last the longest amount of time.
That said it will probably will go away eventually the lighter and lighter you can make convertibles, the more you can add kickstands to the super large tablets like the surface pros and the ipad pros. The more easy you can make external modes of input for these 9.7" devices such as active digitizer styluses, and good keyboards in small and light packages. (good keyboards being not desktop good, but instead good enough to type while still being light and portable. Aka something you would type something that has more than 300 words as a response, aka more than 5, but especially 10 twitter messages)