I came into the preseason thinking it would be Dunn and really nothing has changed my mind on that yet. If they are going to successfully incorporate John Collins early on I would think the steadier player might be the best choice as the starting PG at least to begin the season. They can't have THT hoisting step back 3's early in the shot clock. Say what you want about Collins' fit during the first 2 preseason games but Atlanta never could get him to fit long term next to other non-shooting bigs such as Capela.
It's pretty clear at least to me Keyonte might already be the best PG on the roster and it's just a matter of time before Hardy is comfortable enough to start the rook. IOW whoever begins as the opening day PG might be very temporary as it's going to be Keyonte's job in short order. Reading the tea leaves it also appears Keyonte and Ochai are likely the eventual starting backcourt by midseason unless they make a deal for a bigger fish.
Clarkson, Sexton, and THT are all varying types of combo guards and I'm assuming 2 of them get dealt by the deadline. The one left standing, don't really care which one, can be the long term 6th man.