Familiars are a classic element of RPGs that I would hate to see omitted from P:E. As a DM I always preferred that the party had at least one familiar or companion animal along that I could co-opt as needed to relay in-game information to the party without having to break in on a meta-level and thus spoil the mood. D&D 3.X familars and companion animals (F/ACs) are a good starting point, but I'd like to see more natural animal abilities included.
For example, if my F/AC has a good nose, then we ought to get some warning when a bunch of smelly ogres are approaching the party from upwind. Birds are natural aerial scouts, of course, and could be used in conjunction with a cool down period to do just that. This sort of thing, along with play and possible oddball or humerous observations, behaviors, and inter-species misunderstandings can really liven up intra-party interactions.
Bottom line, I very much enjoy having F/ACs along in a party and my fingers are crossed that they'll be an option for us.