I'd like to see PE become a less confusing and frustrating subject than it was when I did it.
I was never the fittest kid, but middling rather than struggling. But PE to me was an endless stream of futile running about. We learned the rules of netball, hockey, rugby, football, tennis etc through endless playing and getting it wrong. It would have been more interesting to me if someone had explained the rules, how to play well tactically, made competitive games a bit more tactically/strategically competitive rather than sort of thrash it out not knowing why one team is doing better until we can all go for a hideous shower.
By about Year 9 PE got a bit more interesting, when we started making it a bit more cognitive - learning about fitness and healthy exercise. A bit more of the "why" we should do PE rather than yelling at us to change into stupid clothes and do something unenjoyable for an hour before a gritty shower. By then my hatred of PE had set in though.
So, for me;
treat it a bit more like a normal subject. Actually TEACH things, rather than just forcing physical exercise.
Don't shy away from a classroom PE lesson or see PE as the primary way to tackle obesity. (Use things like the golden mile/walk to school etc that)
Don't force kids to shower at school if they don't want to. Not having a shower for a few hours isn't going to kill anyone, whereas being naked in front of 20 peers is actually quite miserable.
Stop outsourcing primary school PE to external "coaches". It makes PE into a subject that's too different for the teachers to teach. The normal primary school teachers cover everything from religion to how poo is made to how to read and add up, yet somehow PE is beyond them? Gives a strange message.