Erh - I do not use Applescript - but I was intending to use OmniGraffle to make website wireframes.. I think it's quite normal to paste website content into the program, for many reasons. And that's where the bug arrises for me.
The bug has been there for over 4 years, where web content could not be pasted probably. And many people have complained. Thats what I call neglect.
If this is a big problem for you, you should vote with your feet. Contact Omni within 30 days of purchase and you can get a full refund.