The only reason old Ingress players are trying Pokemon is because Ingress is at a stalemate. I've over 170m AP (L16 cap is at 40m) and other than trying to get onyx medals in the different statistics, we have no motivations to continue.
It's nice that they corrected in Pokemon Go the biggest mistake they did with Ingress: only two factions. Unfortunately, it would look as if Team Instinct isn't actually getting a third of the participants, making them hardly a balance changer. But even then, it's much better than in Ingress.
By the way, some Pokemon Go medals are laughable. But I guess they're aimed at casual players instead of hardcore ones.
Finally, I hope they add PvP, even if friend codes are required, that would open so many possibilities for fan-created events (just as trading would for rewards). If there's something Ingress is strong at is at them.
(Edited: Yesterday I took down my first L10 gym. Took me an hour, and fortunately it wasn't built to last, a player got it in range from his house and spends the whole night pumping it up. Pinsir x 2, Golduck, Flareon, Slowbro, Exeggutor, Vaporeon x 2, Gyarados).
(Edited x 2: Fortunately I can earn pokecoins, between 30-50 on weekdays before going to work, and up to 90 on weekends)