You’ve already acknowledged and accepted tablo is what you consider “the best system” so they’re not really comparable.
“Best user experience possible” as you see it. Looking through Feature Requests so many are must haves to make things manageable. Some have been implemented, some requested since it’s inception… and requested. Then there’s not features no one ever asked for. Just to create the best user experience… well, “the best” isn’t going to be a one-size-fits-all.
Here TabloTV concludes:
We were trying to limit the number of options available in order to keep things simple.
It may have been specific to asking for adjusting both start and end times +/- or it may have been a generalized statement - the best user experience is one which doesn’t overwhelm their largest demographic. You have to suspect they do market research before they invest resources into anything… or not.
Buy our DVR - you can put the channels in any order you want 
Probably isn’t really a big marketing mover.
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That’s not to say it’s not a valid feature request. It’s been around for some time. They claim it’s something worth implementing in future updates.