Yes, looking at http://en.wikipedia.org/wiki/Special:NewPagesFeed a reviewer can get annoyed with "a few hours off", also showing different times at different places is really not a good thing. If a single reviewer gets annoyed and stops contributing it sounds like a high priority thing to fix to me.
I am interested in fixing this but waiting for some experts' feedback.
Sure, but that doesn't necessarily make it high priority. "it's leaking data" would make it high priority. "The API for this extension is broken" would be high priority. I highly doubt anyone is resigning in disgust from having anything to do with new page patrolling because the timestamps are two hours off. Setting to normal and CCing Ryan Kaldari in so he can provide any advice you need re a fix.
I think this is a good idea. This brings the behavior of PageTriage more in line with other MediaWiki interfaces. I also think it's fine to implement this in the API since otherwise we would have to compensate for the timezone on the client-side which is much more difficult.