Not police chases? If I were producing/developing the NFS franchise at this point, I'd definitely put a priority on police chases, since games like GT7 are going to have possibly even more customization than the NFS games. At this point, without police chases, NFS is nothing. Well, there's also the partnership with SpeedHunters, yeah, but still.
I'd definitely take a look at police chases in HP2, MW2005, and Carbon, and even HP2010 and MW2012, too. I know the Underground games were very popular in spite of not having police, but I feel like that was a product of how it was honestly the only game with a ton of customization at the time. You couldn't customize your bumper or add a bodykit in Gran Turismo 3 or 4, but in GT6, you could start adding a much larger variety of parts, and now with GT7, it's going to quite likely overtake the customization NFS has to offer at this point, pun intended.