If you mean the end credits scene, there was someone from Oscorp asking Connors if he'd told Peter the truth (whatever it may be) about his father, and Connors yelling to leave Peter alone. Earlier in the film it seemed to me like the Oscorp fellow was implying to Dr. Connors that Peter's father may have been murdered by Oscorp for refusing to help/comply with them, which intimidated Connors into using the serum out of desperation, but it was a little vague (intentionally I assume).
Even if he didn't get as much development as he probably should have (and I don't really like the flat face on the Lizard; even if it's the original Ditko design, on more practical for the actor's motion capture facial expressions, I like the long snout of the newer Lizard), I liked Connors in the film. I had been concerned he'd be an evil scientist type in the film but he felt sympathetic to me, especially given that once he was cured of the Lizard persona he saved Peter from falling and was distraught that he'd killed Captain Stacy. I got tired of them killing off the villains of the previous Spider-Man films at their climaxes so I'm glad they kept him alive in this film.
I haven't a clue what villain they should go with in a sequel. While they should avoid repeating villains, I think the Green Goblin is inevitable given that Norman Osborn is a character to be introduced and he's Spider-Man's greatest foe, and that Venom probably deserves a better film portrayal. Doc Ock shouldn't be revisited,, obviously he was done excellently in the last trilogy, but you only have so many Spidey villains (though he has a great rogues gallery, one of the best) that can carry a film. Plenty can carry an issue of a comic, but a two hour film, not as much, especially given that a sequel will not have the origin story to fall back on, they have to carry the whole film.