I'm thinking of getting DB and am reading through the forum to see what the bots limitations are. Can you please explain what is out of the devs' control that prevents 100% afk?
Unfortunately, community profiles are made by anyone who steps up to create them. This can be anyone from amateurs to professionals, but usually the real programmers are busy making plugins. A majority of users take the time to learn how to make their own profiles and do so privately. To answer your question though, there is only 2 factors currently effecting the afkability for act 1 bounty profiles and that is:
The bot doesn't properly recognize when it's using waypoints, so it sometimes completes profile tags while screen is loading - this leads to unnecessary profile restarts, which lead to stucks. (Improper syntax, junk code, bad if/while conditions in the profile itself help cause this, too

).
The bot can see SNO's no matter if they've been used or not, if it's a destructible, then the bot no longer sees this object. Because of this, it's hard to do have profiles do events or objectives where a lever has to be pulled to open a gate. The way we've gotten past it the last 2 years was by objective ids, i.e. campaign mode. RoS Adventure mode, unfortunately doesn't have a way yet, outside of running down a timer (which would start when the profile tag starts, not when they find the actors.).
Everything else, the profile tells DB where to go and then DB takes over getting incombat, etc.