On the autotargeting issue, we canonically know that the rifles have "multiple target acquisition" capabilities, as per Kira in "Return to Grace". The act of acquiring a target is what the gun operator normally does when aiming the gun; apparently, Starfleet guns indeed are smart enough to do it by themselves. And the difference between pistol and rifle might well be the difference between non-multiple and multiple...
A fairly simple and useful feature would be one where the user presses a special button, or presses the trigger in a special way, when pointing at a target but not yet wanting to fire at it. He can then move the phaser whichever way, but the weapon remembers the target that was tagged, and fires at that target (rather than dead ahead) when the trigger is next pushed.
Such a functionality wouldn't need sights or displays. Instead, the handle of the gun might buzz a bit when the target has been acquired, and lose the buzz when the target lock is lost. Nor would elaborate sensors be needed: at the simplest mode, the gun might fire at the location that was tagged, completely ignoring what lies in that location. At a more complex mode, the gun might track the contours of the object that was tagged with a simple radar-like device, and thus follow even a moving object, but again would not care about what that object was.
Evil Overlords everywhere would rejoice: they could now far more easily do the scene where they aim their gun at the hero, say "And now you see the consequence of crossing me", and suddenly shoot their own lieutenant for having failed to kill the hero as ordered. You don't even have to swing the phaser (in a manner that would allow the hero to knock it off your hand, like all heroes compulsively do in such situations): just tag the lieutenant first, then keep aiming at the hero.
Of course, it may also be that these phasers do have very elaborate and helpful sights. They just aren't physical, but projected. The original TNG/DS9 rifles had weird lumps atop that shone a light at the face of the operator. That would have blinded the operator in most cases - but what if that wasn't a light, but rather an image projector that fed targeting data directly to the eyes of the operator?
Timo Saloniemi