Be in contact with (or part of) the upstream development team -- so the development process is open as well as the license.
Integrate with the rest of your distribution -- there's no need to have two copies of google-gears or other shared resources. The new architecture may help us isolate it better via SELinux policy or other means (chrooting selected web-sites?)
I.E: leaving the binary composition to the distributions was a wise decision IMO.
There were also a lot of speculation about Chrome killing of Firefox or vise versa. Again, this Windows mentality of "zero sum games". We Linux people (and Unix veterans) are used to have many "competing" tools -- Perl/Python/PHP/Ruby, GNOME/KDE, etc. -- Tools like nm-applet and pk sit nicely on my KDE system tray, just like Amarok can sit nicely on the GNOME panel.
In the free software world, most of the competition result in variety of reusable toolkits, each with its own pros/cons -- this is a win/win situation:
Long live Konqi (yes, we want Webkit ;-)
Long live Firefox (Prism, TraceMonkey, maybe even Gecko...)