Look at it this way: a mid range tablet from Samsung will perform worse and may or may not get an OS update. The only mid range tablet that may one-up the S2 is the later Tab A 2016 with S Pen (the 9.7inch one), and that's just due to the S Pen's presence if you want it. An alternative is just get an active stylus for the S2.
Looking at other options, I am not seeing anything comparable to Samsung's tablets from other manufacturers at the same size and price, especially since the S2 is an older model. Huawei's M3 looks good but it's 8 inches. The Pixel C is still more expensive last I heard. Asus has a a Zenpad 3S, but seems availability isn't very widespread and maybe more expensive. the Lenovo Yoga 3 is also a bit expensive.