I doubt that the iPad lineup will get updated anytime soon.
I used to have a 4.7" iPhone 6S and switched to an 4" SE because of the preferred smaller size. I chose a refurbished Air 2 as a tablet for surfing, reading, gaming and even working (e.g. for Logic Remote, several music apps and Pixelmator). The size of the Air 2 is the perfect sweet spot between my iPhone and my MacBook - the mini would be too small.
Keep in mind, I'm not recommending an Air 2 here- i just think it's the better tablet for what i am doing!
Something to consider:
1. don't underestimate the 3rd core of the Air 2. Apple just made the iPhone 7 a quad core device and future tablets might have/rely on more than two cores. So, a mini could age a bit faster than an A8X powered Air 2.
2. Of all the iPads I ever owned (2, 3 and Air 1) the Air 2 drains its battery fastest. This IS a disadvantage, it's not a deal breaker though.
3. In iOS 10 the Air 2 feels smooth as silk.