2. Taylor has shown a far higher level of play in his history
Let's set aside Taylor's two starts this season considering they were objectively every bit as bad as Ridder's starts. Despite this, you have a veteran quarterback that had a great playoff game and has a far better resume than Desmond. This isn't to say that Heinicke is going to greatly improve in Arthur Smith's system but the veteran is unquestionably the far more proven player.
While the mistakes were aplenty in Taylor's starts it is worth noting that the offense scored more often and moved the ball a bit more consistently. It is hard to reconcile that with the poor decisions and misses we saw from Heinicke but this offense was better under the veteran.
This will be a great chance for fans and more importantly the front office to see just how bad Smith's system can be no matter the starter. Heinicke is a last effort from Smith to breathe life into his offense and find a way to sneak back into the playoff race.
It is hard to believe that this team is capable of beating the Colts, Bears, and Saints even with improved quarterback play under Arthur.