Sonos was recently modified to allow broadcasting via WIFI without a Bridge or Boost. This is a great option. I would suggest a further, related enhancement. In large homes it is common to have 2 or more access points to provide strong WIFI throughout the house. The current deployment of Sonos over WIFI works with multiple access points on the same subnet only if you use the same SSID for all access points.
While there are some advantages to using the same SSID for "roaming" it is often found that many phones and laptops do not automatically switch to the stronger signal of the closest access point if they can still get a signal (albeit weak) from the further access point they originally connected to. To address this many of us use different SSIDs (still on same subnet) so users can manually connect to the stronger signal if desired when moving around the house.
Unfortunately the current Sonos iphone software will not find you system if you change to a different access point with a different SSID even if still on same subnet (although computer software with a wired connection to the same subnet will).
Ideally Sonos software would be modified to allow both control from a different SSID on the same subnet, and the Sonos system itself to span multiple access point on the same subnet whether using the same or different SSIDs. Currently the work around requires mulitple Bridges or Boosts. Pretty much all other devices on the same subnet can see each other regardless of which access point (SSID) they are attached to, why not enable this for the Sonos system?