Getting every expansion with the base set for Legendary Marvel was pretty overwhlming. It's like 1500 goddamn cards. It took me 2 nights and about 4.5 hours to organize it all and I'm not entirely staisfied with how I did it. Same with Warhammer Conquest, really. FF could easily have made the base box much better for card storage. I hope the Tyranid expansion fixes that problem, but I'm not holding my breath.
On the other hand, the Smash Up Big Box is amazing. The Pretty Pretty expansion came with 4 beautiful dividers and fit in the Big Box with all the other expansions with considerable room to grow. I put away this expansion first and it served to highlight the storage flaws with both Legendary and Conquest. I'll probably make tuck boxes for Conquest and split the Legendary cards between 2 different boxes.
The organizing is pretty fun though