Replace Illustrator? In your dreams
I've sworn by Illustrator since the late '80s although I -- like many others -- am more than a little bugged by Adobe's subscription-based profit grab. When upgrading my equipment a year or so ago, I spent a little extra time and was able to rustle up a real, physical copy of CS6, which I plan to stick with until I retire -- which, to my relief, isn't that far off.
Just for the hell of it, I tried out the OSX version of Inkscape on my MacBook Pro, and god damn, what a friggin' mess. It wouldn't import my Illustrator files cleanly, and the interface looks like a mid '90s version of Corel Draw for Windows 3.1.
Feature-weak, makes a big mess out of my Illustrator files, and a butt-ugly interface on top of it.