Lois and Clark/Superman have won the DCwomenkickingass "best comic relationship" poll every year she's had it. Pre new 52 and post new 52. They still won it this year even after DC's stunt with Superman/WW. And it wasn't a close vote. Lois/Clark annihilated the competition every year.
You may get different results depending on where you ask the question....but Lois and Clark are arguably the most famous and beloved comic book couple in the genre.
This all may be true, but this also has nothing to do with Comic Book Movies.
My point with this is....you are also talking about raised stakes.
Man of Steel was NOT a romantic movie. Now, we can talk and debate about whether that was a good thing or a bad thing.
Personally, I thought what we got from Lois and Superman was great and there is clearly room to grow. But the script itself was not focused enough on their interactions.
Then you add that Superman and Lois have 75 years of expectations and emotional baggage. They've had a TON of really great moments at this point which means that it takes MORE to make us sit up and go, "This is the best ever!"
Tony/Pepper had a huge adventage coming into Iron Man because...there were NO expectations. People outside of comics had no idea who Pepper Potts was.
It's just a very hard conversation because Lois and Superman, for better or worse, have so much iconic history at this point and so much "perfection" in other media that to get to a level where you can say "best" is just going to be really, really hard.
All that said, I think you could tell throughout the interview process that Henry and Amy continue to get to know each other better and seem to really, really like each other.
I think the potential is there for really sparky stuff in the sequel. I hope Snyder isn't stupid enough to blow that. That said, I did enjoy what we got which was two adults connecting in a way that was based on mature trust and respect because I don't think we get that a ton in movies about 30-somethings.
