Don't worry Fynn, they'll probably add updates and expansions to the original 151 pokemon. They'd want to know there would be a market for them taking the time to implement the next generation's pokemon. Whether or not they'll be free or not depends on the cynicism of the person.

And like Psychotic said: it is very much a casual game. I don't have it, because I don't really own a smartphone, but the paring down of the battle system and emphasis on collecting makes it more casual. It's a neat idea, to be honest. It's getting people to venture outside and take longer or different routes walking (sometimes towards a mugging, admittedly).