The Top Paid category in the channel store on the device has been messed up for quite a long time. It was pretty obvious, considering the "Top Paid" channels were always a subscription baby content channel, a karaoke channel, a Spanish language training channel, and a channel with nothing but cycling videos, etc. Every one of those seems awfully niche to be the most popular paid channels. It also only included channels that were direct pay, which prevented any channel with in-channel purchases/upgrades to be included.
With that said, a couple of my channels have spent a fair amount of time in the category, and I've seen a dramatic drop in sales since it was taken down (~70%). Hopefully Roku has plans to re-add it using better metrics... or, better yet, can provide some way of increasing visibility of channels after they've dropped out of the New category...
I've always thought a Recently Updated category would be very useful, so users could easily find out if/when a channel receives a major update. Inclusion in such a category would likely require some sort of opt-in option during submission and additional review, to avoid channels abusing it just to increase visibility.