Ach, I'd hardly say I'm any expert in the area, but it just seems like something that hasn't been fully explored yet (though we know many of the weaknesses).
I don't think dutching should have any major 'gameplay' influence, as long as the players can orientate themselves in relation to their previous position and angle. Are you suggesting dutching the camera 'live'? There's a great example of that in the intro to Silent Hill...
Relatively easy to program but unsettling as all hell. =DAnother thing to think about is the controls - many people hate 'tank' controls, but at least they stay consistent and player-relative across different camera angles. Camera-relative controls are more 'intuitive', or immediately familiar, but as the angle changes, so does the meaning of 'forward' for the character. There's some ways to get around that -
1) you don't change the axis everything relates to until the player
a. rests the stick or
b. pushes the stick X degrees away from the heading they were on when the camera changed
2) You interpolate the reference axis towards the new camera reference over a few frames - can feel a little loopy, but players can perceive the change progressing and correct, it's not instantaneous.
3) Take a trick from Heavy Rain and assign one button to 'walk forward', while the stick only directs the attention of the character. Ideally, that way you don't feel the change in cam angles if you're just pushing 'walk forward'. It's like a combination of tank and cam-relative controls. It's still not perfect, by any means, but it's pretty interesting.
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Maaaan, I really want to find a place to talk about all this stuff! =/