Obviously that would be the way to go, start out strong. But consider the reception for F&F franchise for the first 3 or 4 films..... downright horrible, and it wasn't until Fast 5 that the films turned a corner and look where they are now. It can be done and should have been done by WB taking the tried and true approach. Obviously the MoS reception hurt the cinematic universe out of the chute, but recovery is just a matter of finding the director and voice for the franchise and mapping things out appropriately.
The first 3-4 FF films weren't received horribly by audiences. Audiences loved them. That's why they kept making them. Critically you're right, but that's not what matters.
Very true that Fast 5 took them into the stratosphere but all of them were relatively successful except maybe Tokyo Drift. You can very much evolve a series like Fast & Furious or even Mission Impossible into juggernauts but I don't think a character like Superman has had that luxury. Superman is a much more expensive character to bring to the screen and he already has a mixed public reception (unfairly imo).
Sure MoS2 could've realigned things but I don't think it would've a surefire win commercially unless they end up making a TDK level movie and that's way easier said than done. Superman has a lot of baggage and making a direct sequel to a incarnation of the character with a lot of baggage just doesn't seem like that good of an idea to me.
I think what they should've done is do similar to what was done with Hulk. Have Superman appear in some team up/cross over movie and get the audience to go ga-ga over the new portrayal and then try to make another movie.
Let's say MoS did what it did and they wanted to push on. Aquaman, Flash, Batman, Wonder Woman still could've gotten solo movies and then you make JL where you "fix" the DCEU portryal of Superman. That's less risky and possibly could be just as effective. I mean you could do the make the sequel cheaper option, but I just don't think Superman is a character you want to go cheap on and even making a cheap Superman movie would be pretty expensive
I just didn't see the large demand from the general audience to see Man of Steel 2. Batman Begins didn't do great at the box office, but there was still a HUGE demand for a sequel eventually due to merch, home video, and just word of mouth. I don't see that for MoS2, so to me a better idea would be going the Hulk/Avengers method except you know...actually capitalize on the character's reception in the team up
EDIT: I'm trying to think of or find a movie series where the first film got mixed reception and then the 2nd movie came out, was received better, and was a huge success. I'm sure there's an example out there, but I'm drawing a blank
oE comes to mind, but it wasn't successful in the BO. I think it would take a special series like a superhero film to pull it off. MoS2 might have done less in terms of BO than MoS, however I believe if they course corrected the franchise with a better story, then you are setting up the rest of the universe for success. 
