The codex being implanted into Clark was symbolically huge - he was the amalgam of all krypton merging with the best qualities of humanity. The device, plot wise was only important to zod because it was what he needed to perpetuate his purpose as the one to ensure the survival of his people. It didn't need a bigger payoff than either of those things in the context of this story.
Them repeating a little info about krypton was necessary because Clark needed to be privy to it as well. I guess they could've done some quick cutting with the idea that jorel was 'showing' him what had happened, but it didn't bother me at all. The way it was done made more sense and frankly every idea I hear in this thread tends to be very cliche and retreading very bland ideas used in many of the marvel movies. There's one post that wanted to use like 3 very cliche ideas from three separate marvel films in ONE superman movie. I would much rather have what we got than to re see those moments again.
I swear, more people complain about what they think things should've been, rather than what's actually presented and the flaws actually there. Having said that, everyone's entitled to their opinions, but I certainly don't agree with much of the 'criticism', much less their ideas on what could be done to fix them.