George,
If I am understanding you correctly:
You listed a couple of requirements that you say you see no use for. Schematic symbol assignment to parts, pin assignment to symbols...... Things the packager pretty much handled for you before.
I'm working on making the migration from PADS Flow (Logic - Layout) to Central Libraries. So my perspective is that if all thing you see as useless are done well, I see no use for a packager.
And that might be the confusion created by the new Central libraries. They are trying hard to merge the best of both worlds, but those worlds were quite divergent.
Coming from my perspective, I think it's easier to understand the concept. PADS Flow libraries started with a Part Type. For example, a 74LS03 NAND gate. A Part Type is created, I'll call it 123456 (company part number). I add whatever properties I need (Part number, description, etc). I attach to that a NAND symbol. I can also attach another symbol, with a different graphic representation of a NAND gate. Then I assign pin numbers to the symbol. Then assign a PCB Decal, say a SOIC14. This lets me use that same NAND symbol with many different parts, with different pinouts (Quad, dual, single) and I can assign that SOIC14 to any other number of parts. As soon as you place the first gate on a schematic, all of the part information is there.
This is why you must have everything assigned in the Central Library.
Now, where it gets dicey is that xDxDesigner is symbol based, not part based. So the Central library is still driven by the symbol. So it's hard to resolve things like multiple symbols that describe one part, or duplicate symbols used to describe different parts.
The Mentor team took on quite a task to create Central Libraries that can be migrated to from both a symbol based, packager driven and a part based, library driven scheme. They are listening to users to get this right, but it's not going to be easy. I'm glad I read your post. I've been talking to Mentor about the frustrations I'm having migrating from PADS Flow, it's helpful to remember others are migrating from Netlist Flow.
Pete