This isn't directed at you, you are simply following the direction of your superiors. To me is sounds like a corporate decision that was made many years ago when Serif decided to make Publisher. From a financial perspective creating an import to attract new customers from Adobe would seem to make sense. Leaving the customer base you acquired over many years out in the cold is not a good way to get those customers to recommend your new product. Without a massive advertising budget, one of the best ways to get your product into the hands of new customers is word of mouth. If you tell your current customers they are not worth the coding time to create a viable importer from the previous version of your software they will be unlikely to promote your product to their peers. It shows a lack of commitment. I know that Publisher doesn't have all of the features of PP, like 3D objects, Warp, and mail merge. I can't even use Publisher for my company's purposes until it has mail merge. I use mail merge several times a week to create our donor receipts. I would hope that over time these new features would be added. Perhaps Serif could promise an importer once Publisher is more fully developed rather than saying they're not even going to try. The response to your current customer's requests for a direct importer from PP tells all of us who have been using it since the 1990s that you don't care enough about us to spend the time. Why should we recommend your new product to people who use your competitor's software when you haven't been loyal to us.
Definitely would like an import from .ppp. I've been using PagePlus for over ten years so you can imagine I have more than a couple files floating around. One thing we use it for that I don't see on Publisher is mail merge. All of the receipts from our mission are created using PagePlus through a mail merge. One other feature the Publisher doesn't seem to have is the ability to convert shapes into text frames or picture frames. I use convert shapes to shaped text frames on many of my publications.