I don't think a pickup is the best idea for them. Nobody who knows Mitsubishi in the US ever thinks of pickup trucks. What we think of are the Montero and Evo and off-road motorsport in general. What they need here right now - what they've needed for years and would've been making money hand over fist - is a new Montero. They need it now because the 4Runner is a dinosaur with no replacement in sight.
Weirdly, because Australians have such a strange taste in pickup truck and SUV packaging and design, the American-market Outlander which they shipped to Australia has a much more appropriate truck-like SUV design than the Australian-market Pajero Sport. But I still think the Pajero Sport would sell here, particularly if it came with a Ralliart package or whatever Mitsu is offering these days. There are people out there buying brand new Lexus GXes specifically to go off-roading and the Pajero Sport offers similar capability for much less money. 4Runner TRD Pros are flying off the shelves at a ridiculous rate. There simply aren't any other competitors in the reasonably priced full-enclosed off-road SUV market.