For me, in COD4, the built-in server finder was always buggy as hell. Half the time it would only find a handful of servers rather than the full list, forcing me to always manually enter ip addresses. PunkBuster has bitten everyone here many times, causing you time to try to fix (re-installing, updating PB) while everyone else is playing. Not to mention steam auto-updating the client while all the servers are still at the older version. Lots of frustrations with trying to get into (or stay in) a multiplayer game.
While I personally felt the single player was great, the multiplayer was where it was at (once you actually got in). We all spent countless hours playing COD4 via multiplayer. Doesn't sound like the changes will impact our weekend gaming, so that's good, especially if the changes fix all the problems i listed above.
But, unless they change their plans, it sounds like LAN gaming is definitely out, especially for competitions at the big lans.