Wired sensor network
I think CAN is a good choice IF:

You can live with less than 1 Mbit/s.  100 m is too far for that speed.  The worst case delay just due to distance is the out and back time between the two most distant nodes.  That's 200 m propagation distance in your case.  Let's say that the propagation speed on the twisted pair is half light speed, so that comes to 1.3 &micro;s due to propagation delay alone.  That out and back response needs to happen usually within about 2/3 bit time for the collision detection to work properly, so that means you're exactly at 500 kHz from the above numbers.  I'd say 250-350 kHz would be a reasonable speed for such a CAN network.

You can have nodes manage multiple sensors.  200 nodes on a single CAN bus won't work with some bus transceivers, like the common MCP2551.  I vaguely remember it is specified for up to around 110-120 nodes.  Check the datasheet.  If each module handles just 2 sensors, you're within spec.  If the 200 sensors are evenly spaced over the 100 m, then a quad-sensor node only has to have a reach of 2 m, or up to 1 m cable to the actual sensors.

It's probably smart to design quad sensor boards anyway.  You can still use them to handle individual sensors when they are far apart, then 4 at a time for a clump.