It was strange. Zequiri came on against City and done well, so surely makes sense for him to come on again and build on that 'form' and confidence. It did feel like a 'pick a name out of a hat' type of substitution, I can only assume Potter thought he might be better option for counter attacking.
That's a performance and result to forget, but nevermind. There's clearly some promising players to get exciited about next season and we can only hope Bissouma stays another year (I still live in hope).
AJ has done pretty terrible overall since joining the club. No system is going to change that. He's had enough chances now. Hopefully he moves on and does well at another club (so long as it's not in the Premiership!).