linux-vserver is not contemporary with zones. If you think that it is, you haven't looked at Solaris zones technology very carefully.
linux-vserver requires the kernel to be patched; Solaris zones does not.
linux-vserver has no clustering or process migration capability; Solaris zones in combination with LDOMs gives you a path for live migration.
linux-vserver networking is based on isolation, not virtualization. This means each virtual server can't create its own internal routing or firewall setup -- Solaris zones can.
linux-vserver doesn't fully virtualize the system; clock, parts of /proc and /sys are not virtualized.
So no, linux-vservers are not equivalents.
Yes, docker offers containerization -- but not sufficient containerization. Certainly not sufficient for security purposes as have come up repeatedly in recent history.
As for the "weight" of zones; I don't know what "weight" you're talking about. Solaris zones have almost no overhead at all. They use some disk space, but we're talking less than 300MB if I recall correctly at most in a default configuration. And Solaris Zones give you several advantages that Docker doesn't provide.
Regardless, I'm certain that for some specific use cases, Docker will prove an appropriate technology.