Interesting question, Dat. Of course, you'd have to take that stupid lift fan out to make room, which might be a problem. Or move the fan back and take out even more fuel - but then the term 'long-range' would be even less appropriate.
There are better jets to do long-range interception, in my opinion, but the systems and cockpits of today make that a perfectly viable single-seat role anyway. JSF is still more 'strike' than 'fighter'. Some of the other roles you mention could be done by either, but some scenarios COULD benefit from a two-place a/c. Perhaps a bigger issue is using such an expensive asset to get in close and mix it in the battlespace (or is it battlesphere today?); the 'close' bit could fut JSF in an environment where it derives little protection from its stealth, whilst being disadvantaged by its other characteristics that have come about due to the compromises that stealth demands.
Hey, here's a thought. Maybe they could design a WSO pod to go in the weapons bay. It could have all his displays and controls in it and a plexiglass nose section for visibility. If required to look outside, the bay could open, pop him out in the airflow and then put him away again when no longer required. Even better than the 'nav-in-the-nose' Canberra. As long as he doesn't get launched or dropped.
