Banana texture is the worst.
When I try to eat a banana, a lot of times I end up just chewing it to death, because my body just will not allow me to swallow it.
This already exists. There's a banana (in Vietnam, but I'd assume not just there) that's smallish and rounder than most others which has a distinctly sour taste that reminds me strongly of apple. Ymmv, taste being a very subjective thing.