http://www.themarysue.com/the-pokenomicon/
As expected, there is a grand master-plan for this game to continue forever. They will introduce Pokemon over time, playing the long game. I'd imagine they will roll out new Pokemon by generation every time they have an anniversary, but that's just my guess.
They WILL introduce trading; they have plans to make Pokestops more important and/or more objective-based, such as providing modules that turn Pokestops into insta-heal stops for your Pokemon; they plan to introduce friendly battling; there will be team-specific interactions, and probably team-specific chances at catching one of the legendary birds.
They are aware of the three-step glitch, and will fix it at some point, but they are "more concerned with keeping the servers running as the game continues to get released in different places."
AKA, "this glitch makes it a bit too easy to locate and find specific Pokemon, so we don't know if we want to fix it. We'd rather you just wonder around aimlessly in frustration, catching 27 Pidgeys and 38 Ratatas for every decent Pokemon you find."