I think that I've said this before (perhaps on Tama Zone), but I'll say it again... I don't think Bandai Japan should be in any rush to try to better the P's. Technically it is the best (most advanced) Tamagotchi release to date, and how they've created the concept of being able to introduce new characters, locations and items through the pierces is a fantastic idea that they really should exploit while they still can. The P's are still popular, the pierces are still selling, and people still want to buy them and use them, so if anything releasing a new Tamagotchi at this point in time would be unwise. There isn't the need to, as they've been able to keep the demand for the P's constant throughout the year with the release of the pierces every other month.
When they do make a new release (perhaps March or November 2014), the only thing that I can really see them implementing in order to "better" the P's is a 3D-screen similar to that of the 3DS. They should keep releasing the pierces though; and make all pierces currently released for the Tamagotchi P's compatible with the next release.
Actually, I imagine the best addition (in my opinion) would be a Bluetooth connection. They could keep the infrared feature so it could connect to other devices, then add the Bluetooth feature for downloads (and possibly connections as well?).
That would make downloads a million times easier since Bluetooth devices are more user-friendly and readily available (for most people) than infrared devices nowadays.
But I think they should still keep the IR download capabilities since there are IR devices out there and it is good to have more connectivity options.