I don't think you need any inputs other than HDMI with CEC (all current TVs have it).

Even though I would really like to try webOS TV (after having used webOS on smartphones and tablet), I must agree that buying a smart TV is pointless. I am now a happy owner of a Raspberry Pi (with OpenELEC on it) for some months and can't express enough how well it replaced the 'smart' in smart TV for me.

1080p playback (sure, if you need 4K, you need to go for something else), quite fast navigation, endless possibilities (home automation, DVB-T, hundreds of apps, ...). I think that current smart TVs can't do one quarter of what KODI/XBMC does and aren't that user friendly either (at least from my experience). And for the price of $35, it's a no-brainer.