I have seen multiple times people asking about being able to re-program the channel shortcut (aka "sponsored") buttons on the remotes. And i don't read regularly the General, so it ought to be a very popular request - but my guess is not feasible because of contractual obligations to the advertisers. However, here is a fresh idea that i saw recently:
In other words - how about letting users assign an action to the buttons A/B?
"A" and "B" are unused outside of games, so no harm in letting them be useful when in the player home UI. There is even a suitable place where that configuration can be added, Settings > System > Remote (sub-menu avail only on players that support radio remotes). The only action that has been requested so far is to assign a channel-of-choice (e.g. YouTube or HBO Now) to a button, so one can launch it with a single button press, if so they please.
Oh, and this will "magically" make the remotes with A/B buttons more desirable, more "premium" - for no added hardware cost!