Jaguar
" Can't do the job the Harriers are doing" - rest my case.
No, I've never flown a Jaguar but I've never heard anything good about it.
As for "Billions to support, & then sort the aft fuselage" well I have personal experience of said aft fuselage among other updates, but if you're keen for someone to spend billions, please count me in on shares, we should both retire very happily if surprisingly.
I am not a Harrier pilot but have covered most development of it ( 1 & 2 , RAF & some Navies ) & systems, so have seen the good bits & failings - gun could be sorted in a real ( er ) war, - I agree why not now - care for any ACM if you had the chance ?
DZ