Re: Replace Illustrator? In your dreams
If you rate an open source app on its ability to open the proprietary files created by a proprietary application, then yes, you'll find shortcomings. But let's remember, those shortcomings - from a user's point of view - are Adobe's fault for not publishing the specs of its files, not the fault of Inkscape developers who have had to painstakingly reverse engineer the .ai file formats to achieve any sort of compatibility. See http://en.wikipedia.org/wiki/Adobe_Illustrator_Artwork
I think you'll find that Adobe doesn't *like* open source apps being able to open its files as well as its proprietary software can... so (as MS has done for over a decade) it changes the formats subtly from time to time to break compatibility as soon as the open source developers reverse engineer the formats well enough.