I don't know what's the big deal with everyone griping about the SWAT Lizards. To be honest and frank, this seems to fit perfectly with The Lizard from the comics and animated series. Sure, it looks and sounds cheesy, but it fits with the general idea that Connors wants everyone to feel his pain. Heck, maybe there is no way for him to change back and he's stuck like this; maybe Spider-Man or the police, in a scuffle with him, breaks the cure, thus he wants to take his revenge out on them both.
I mean if I couldn't go back to being a human and was stuck as a slobbering, scaly lizard I would want the public to suffer my wrath either by killing them/eating them or changing them into what I am.
And yes maybe it's just the studioheads wanting an excuse to spend more money for a bigger, climatic ending to the movie, but I think the mentor/father-figure aspect won't get lost in the fray of Spider-Man versus a bunch of Lizard lackies.
As for the design, yes it looks a bit like a Goomba and Killer Croc, but Webb seems to be very respectful of the source material going for a Ditko-like look. Peter is more of an Ultimate Spider-Man Peter. Gwen seems to be classic Gwen. Webb, to me, seems to be cherrypicking from a lot of history and lore to give us a great big bang of a show. I don't think he's going to make Lizard into some mindless, monstrous beast or some mad, maniacal scientist, but someone whom, like Ock and Norman before him, made a terrible mistake, changed into something unusual; brought out the darkness in him, and he has to atone for his sins and realize he's hurt a lot of people. It's your typical "Spider-Man" movie formula.
Of course I could be wrong but I hope not.