It really depends on your preferences and what you classify as "easy". For two Over-The-Air channels, a plain-old TV certainly makes for an easy installation - but of course - no DVR abilities. But that's another question you have to answer: some people think DVRs are complexities (more equipment, more UI) but other people think they are simplifications (I don't have to watch some arbitrary channel number at some designated time.)
I've seen some threads indicating that a recent Roku OS release messed up Tablos. I don't know if that's fixed yet, but when you split a functionality like that across several company's products, inter-operational glitches like that do seem likely to occasionally happen. (Most Tablo models - maybe all the current ones - are accessed via an app on a device like a Roku. It lets them create whole-home capability from one DVR but also means they have to keep their own stuff and the roku stuff playing together.)
To be honest, I'm not sure what the Roku is for in your scenario. ie: you haven't mentioned Prime, Netflix, Max etc. or streaming at all. Have you tried the Roku? You might find it's full of other stuff that might be as interesting. Just to make sure we're on the same page: your Roku isn't designed to do Over-The-Air at all. It's meant to stream TV from the internet. As such, Roku has no need for an antenna. But if Over-The-Air is your thing, then clearly YOU need an antenna, and maybe you don't need a Roku. (Tablo kind of sneaks OTA into your Roku by turning OTA into a stream.)
I remember when we upgraded to a color TV. My mom danced on TV in New York in 1942.
