Mind you, I'm just pointing this out. I come down partially on the patience side myself, now that I've seen some preseason.
Fisher keeps saying the criteria for starting Goff is "when he's ready".
How will the Rams know that once the regular season starts? Won't Keenum be getting the lion's share of 1st team reps as they prepare for each game?
Now if Keenum and the Ram offense are quite successful, then your "what's not to like?" question becomes more applicable.
Conversely, if it falls flat and hard, then switching to Goff becomes more obvious regardless of his state of readiness.
But the situation is LIKELY to end up being more muddled than that.
What if Case wins 1, loses 1, wins 2, loses 2, then wins 1, loses 2 again?
What if there's a lot of question and varying opinion over whether and how much he and/or his limitations have to do with the losses?
At what point in there should Fisher replace him with Goff?
What if the Rams are winning, but Keenum doesn't seem to be the winning factor? Should Fisher mess with that even if he thinks Goff is now "ready"? There would be risks in doing it, and risks in not doing it.
Once Keenum is declared the regular season starter, the whole issue of when to replace him becomes sticky, unless it's disastrous, which none of us want it to be.
So then you could end up with a season where it was just never quite the right time to replace Keenum, but the record still ends up being 7-9, 8-8, and at the end of the season we're saying "might as well have started Goff and gotten him his first year under the belt."
Just lawyering the other point of view.