I'd say Wreck-It Ralph deserves a sequel more than anything else. I'm hoping they get to revisit concepts they didn't have time for in the first, like that Sims/GTA mashup that would look to be a satire of online gaming. That and more time spent with the other Sugar Rush racers.
The makers of Wreck-it Ralph want to do a sequel no doubt. I'm sure Disney would let them make one in time, but don't expect it that soon. The writers have hinted at Fix it Felix Sr. so that's got to be a good source of character based storyline for Felix. And yeah, Big Hero Six should have a second film. The first one was the origin story, and since there's a big super hero team there's bound to be newer villains out there. It's just a matter of making sure they can capture the same heart. I'd say Ralph and Hero are the best Disney's not Pixar studio have done to the point where they've actually surpassed Pixar in quality.
No doubt, however, Disney is considering Frozen 2. Before the hype backlash strikes up, remember the movie made around a
billion worldwide, and even Disney didn't think it would be that raging successful, since most of the merchandising has come out
after the film. It's only natural they'd want even more of that money, especially since Tangled and Princess and the Frog didn't make as much as they wanted, but were still moderately successful, but didn't really break the boy barrier. It's just that in terms of storytelling they shouldn't. There's nothing more to add that won't make it a mission pack sequel. Not when Hero and Ralph have heavily involved worlds and concepts that only the surface was scratched of. I mean, the very least, Hero deserves a cartoon series and a
new line of Marvel comics based on the movie characters.