Clearly the Galant, lancer, and Mirage aren’t going to cut it any longer. In the 90's Mitsubishi was killing it in the US, and awesome brand equity disappeared within a decade. Here’s how to be relevant again in the US.
1) Bring the Pajero back to the US. The Monster was a 9/10's Land Cruiser for 60% of the cost. It was a Land Rover with Japanese build quality. The Sport looked awesome and sold great. Forget te crossovers, bring a real 4x4 back. It goes toe to toe with the Everest and the GX470/Prado overseas, let it restore brand equity here too.
2) Do something with the Eclipse. Make it smaller, make it lighter. Think FWD BRZ. Make it simple, cheap to buy and easy to modify. Go back to gen I and gen II roots, before going off the rails with 3&4.
3) Bring back the Diamonte. Sure, it’s an Infiniti, but the hybrid Proudia would fit the bill nicely.
4) Bring the Triton. Nuff said.
5) A proper sports car. GTO/3000GT.