I agree with you that PP could really benefit from better meta data support. In some respects, I think 1.6 was a step back and a step forward in terms of EXIF support. Moving this information into the database was a wise move, because it can keep all image processing functions contained to the admin panel, and makes it a lot easier to work with this meta data. However, the new exif functions ignore the maker note entirely, which leaves Nikon users out in the cold because that's where they hide they ISO information as well as other useful data.
I think the biggest thing holding the Dev team from switching to a more sophisticated EXIF system such as PHP Exif Library (PEL)
or PHP's built in EXIF reader, is compatibility. PEL requires PHP 5.0, and many hosts don't configure PHP with EXIF support, so moving to either of these systems leaves some PP users or potential users with no upgrade path.
Ultimately, it will be necessary to leave the 1.x series to die, maybe providing security patches as they are needed, but stop development of new features and move on to PixelPost 2.x.