Clark's ability to forgive is momentous. I can understand Martha and Jonathan's forgiveness of her crime against Tempus, in order to save their son 1000-fold; such forgiveness is easy.
Death gave Lois and Clark a blank slate on which to rewrite their love and their future. I doubt it's a course anyone would recommend, but dying and being reborn healed the wounds previously made, whether by Doomsday or by Lois. There will still be nightmares, how could there not be. Not to sound cliche, but Clark dying was worse than Lois breaking his heart. If he was going to live, and miracle upon miracles he did, therefore he should live the life he wants, and not the one he dreams of.
Lois merely wants a second (or third) chance to finally love Clark right. The Kents forgiveness allowed Lois to forgive herself. We knew that Clark's ability to forgive (especially Lois) is greater than anything else. I don't think what I'm trying to say is coming out well, because I'm tired and it's late.
Still had me sitting on the edge of my seat wondering how to fix Lois and Clark's cookie jar and fixed it you did. Let's hope it's stronger than before.