Viera Link is the way they talk to each other with HDMI-CEC, so they both have to have it. Like, when you put in a Blu-Ray player it will switch the source on your TV to Blu-Ray. The other features are fairly redundant.
Most of it really doesn't matter one way or the other. The web browser will suck compared to a real PC and most people will never use it. It's not like your TV will be running a standard IE / Chrome / Firefox client. Pandora will be iffy and the Netflix client will be terrible. Even if it is tolerable it will probably never get a software update (unless MAYBE there is a single bug-fix update in the product lifecycle).
The point is if you want Netflix (or any of the other online stuff) you'll be better off with a $99 Apple TV or $50 Roku box or a PS3 or Wii because those are widespread popular platforms that have solid software and actually get updates. When Netflix went to 1080p the Roku client was updated immediately. And the PS3 was updated a couple months later. But it's not like any Blu-Ray manufacturers went and sent out software updates.
Wi-Fi is nice, of course. If you do find any of the online features useful (or use the smarphone remote control app, which looks cool because you can stream stuff from your phone to your TV, too) you don't wanna have to have to worry about where you're going to route an ethernet cable. And blu-rays can have online features, so it's nice in the BD player, too.