Not sure if you followed it, but we had the Carbon vs Cocoa recently over in the Mac forum. I couldn't find any evidence that Cocoa would be faster than Carbon (rather slower due to the dynamic features of the Obj-C language). There are a few features in Cocoa that are not available to Carbon apps, but these are some OS X-only features that wouldn't make sense in a cross-platform 3D app (judging from your article, you're not very keen on an embedded Safari web browser).

Carbon as a porting path was the plan 4 years ago, but Apple has changed its mind in the mean time. On every developers conference they stress that Carbon is a full citizen of OS X and that it's here to stay and that it will be updated.

For your reading pleasure, a few related links we threw around in the other threads:
http://blogs.msdn.com/rick_schaut/archive/2004/02/10/70789.aspx
http://www.unsanity.org/archives/000024.php
http://www.unsanity.org/archives/000111.php

About the Cloth room - sounds to me like you'd be happier if "drape from zero pose' and 15 draping frames were the default? Or am I misunderstanding you? I don't know how Rhino works, but I guess it's a bit easier there as the user can put the mesh in any shape before draping, where Poser, not being a modeling app, needs to go other ways.

A polygon->NURBS conversion would not make sense here. Converting a whole polygon mesh to one NURBS surface is not possible, as NURBS have certain topology restrictions that polygons don't. Converting each polygon to a separate NURBS surface would obviously not be of any advantage, as it'd be causing more instead of less overhead.