It's interesting you bring up that you want an Arkham City/TAS style film but you're not too excited about having Loeb or Dini on board.

I was actually thinking about how to make it closer to AC and the best I could come up with was "Older Bruce. Dini/Loeb. Del Torro and Nick Arundel".
Funny you bring up the Penguin - he's one Bat-villain I've never liked. I just find him so annoying and I can never take him seriously. I can take Calendar Man more seriously than Penguin, funny enough. And if they were to use Calendar Man, I'd want him to have been locked away already with someone mimicking his M.O. à la "Holiday". The "Holiday" alias could be attributed to the reveal of any one of the aforementioned characters as a "villain".
Yeah, I agree with the bit about Nolan's trilogy. I mean, unless they make a film series which can sustain an Arkham City tone throughout its entirety.