I haven't seen one of these for years.
As for some ideas for starters, maybe forward sweep the wings, make smaller but more angular canards, remake the tail fins, and some variable thrusters. Make the intakes proper intakes and loose the gimicky missile launcher. A mountable rail gun could be quite cool - say underneath the craft. The nose needs some work too - maybe a bit more traditionally pointed
Maybe add some louvered vents where the silver bars on the rear are located and upgrade the landing gear. Finally, a splinter style camp job in black and grey would look quite cool.
They're my inputs, but I'm sure someone would come up with better suggestions along the way :)
Look forward to seeing what you do with it