Hello and thank you for taking the time to read this suggestion.
I am currently in the process of trying to catch 1 of each pokemon. And this number is nearing the 800s with the cap being 900. I do not know if you guys would consider increasing the cap. My personal suggestion would be increasing this cap based on pokedex. If you have a certain obtain/seen/evolved. Other options would be a quest you can do to increase it. Pay poke dollars for more slots. I know this would be a very low priority just wanted to throw the idea out and see what you think.
Thanks!