I've been saying this for years in all the Lizard threads, but no one listens to me
Plus, Lizard was at one point in SM2 in the early scripts, and you can see it when you watch SM2. You can tell that subplot got merged into Ock, and it worked for SM2 very well.
Plus, Connors has no build up before becoming the Lizard in this one. He is already the Lizard or quickly changes. With a new cast, a lot of our sympathy we have for him is not there. With Baker's Connors, we knew him. We liked him. That would have had more drama. Doing it in this movie I don't see working, or getting us to care like building up over an entire film to the Lizard would have.