It's excellent that you're working on something in this direction. Perhaps you'll find a few comments useful:
1. You state correctly that "The UFO is what is called a package and packages are a well established file structure" — however, you omit the key portion of the sentence. Packages are a well-established file structure on Apple operating systems (Mac OS X and iOS). They are virtually unknown to other operating systems (Windows, Linux/Unix), which makes them a far-from-universal solution. The Apple packages are a great invention, and I personally love them — but they're tied to one particular vendor.
2. When you say that ZIP is "absolutely terrible", then I trust your judgement. But I must add that it's in good company: PDF, OTF, HTML, VFB and UFO are all "absolutely terrible" in some ways, and good in others.
3. I'm not an expert of file storage systems. However, I cannot help but notice that a ZIP-based container that stores multiple files has found extremely wide adoption in the software industry as a document storage format. The e-Book EPUB format (.epub) , the Microsoft Office 2007 and later formats (.docx, .xslx, .pptx) , the Open Document Format (ODF) used by OpenOffice and LibreOffice (.odt, .ods, .odp) , the Adobe Acrobat PDF Portfolio format , and the Apple iWork format for versions 09 and earlier (.pages. .numbers, .key) *all* use a ZIP-based multiple-file container. Some of these container formats (most notably EPUB, Microsoft Office and ODF) are international standards and are well-specified. Some of them restrict the feature set of the ZIP format to a stricter subset, some even disable ZIP compression, but "going the ZIP way" seems to be their preferred choice.
4. Apple’s iWork was a curious case: until iWork 09, Apple used a dual method for storing their documents: a .key or .pages document could either be an Apple package (i.e. a folder with the extension .key or .pages) or a ZIP archive (i.e. a file with the extension .key or .pages), and the iWork apps treated them fully transparently. When iWork was ported to iOS, Apple changed the file formats, and currently it’s a hybrid (a package containing ZIPs) .
I'm looking forward to your talk. I would be keen to hear what exactly makes ZIP an "absolutely terrible" choice. Perhaps you might even choose to share why you think so despite the fact that Adobe, Apache, Apple, Microsoft and other major vendors widely chose a ZIP-based container as their storage format, and some even went through the process of international standardization.
 Wikipedia: Package (OS X)
 International Digital Publishing Forum: EPUB Open Container Format (OCF) 3.0
 Microsoft Corporation: Open Packaging Convention, in: ISO/IEC 29500-2:2008, Information technology – Document description and processing languages – Office Open XML File Formats – Part 2: Open Packaging Conventions:
 ISO/IEC 26300:2006/Amd 1:2012 — Open Document Format for Office Applications (OpenDocument) v1.1
 Adobe Systems: Universal Container Format
 Sean Patrick O'Brien: iWorkFileFormat