How high end would one have to go?
Just the norm specs that compete. A tale tell sign of crap is a lack of any real settings, meaning only the basic minimal settings.
I can appreciate wanting to have your Smart functionality already integrated. The problem I have is the inconsistency in both UI and performance. Unless you buy/replace all of your TVs simultaneously, you're not going to have the same functionality in all of your TVs. We have 4 TVs from 3 different manufacturers, only 2 of which have Smart functionality built in but from 2 different manufacturers. The UI on each TV is completely different, as is the Smart functionality. IMO, it's much easier to just hook up a 'smart box' (Roku, Apple TV, Chromecast, etc) and have the same user experience on every TV. This is especially beneficial when you have a wife and young kids.
I'm hoping to have my TVs for quite a while--great Smart features now likely won't be so impressive in 5-7 years. And if you think manufacturers offer lackluster support updating the OS on their Android phones, they have nothing on manufacturers offering updates to TV firmware. It's much easier just replacing the Apple TV than it is the TV itself to get the latest Smart functionality.
That makes sense. I myself don't really use anything that I wouldn't have to sign into, so dealing with differ interfaces doesn't mean much for me when Netflix, Youtube, and most other apps are basically the same across platforms. I can stop Netflix on my Xbox 360 and resume right where I left off on my blueray player Netflix app. I plan on getting another TV soon and rather apps be integrated instead of having to buy another device or move my existing devices back n forth. As my Xbox and bluray is not small like a roku or AppleTV to keep moving. I can understand for those who already have these small devices or a device for each TV already.