Why cant we battle each other? Pokemon improvements!!
I think it would be good if we could battle each other for exp points or even stardust. I also think we should be able to trade people from far away instead of being next to each other. It would be good to at least have one magikarp community day. There are so many things that could make this game more fun for people around the world. I really think the battling and the trading could be good. Maybe also being able to at least do short messaging to people with prewrittem comments like "want to trade" or even "want to battle?" Stuff like that? Or asking if you have a certain type of pokemon.
Answers
A lot of people would be very underwhelmed with a Magikarp community day. They'd have to give it both a new fast move and a new charge move to make it at all exciting for people who already have the gold medal and several shinies.
Opening up trading for people who aren't close to each other instantly destroys any value regionals have and makes trading for distance trivial. This one is not happening no matter what, the limitations are in place for a reason.
A PvP system has been speculated and rumored for a while now. Niantic apparently said they would "like to have it released within the year" which too many people have taken to mean "it's coming out this year." Personally, I think some heavy changes need to be made to combat for a PvP system to be anything more substantial than a speed tap-fest.
Niantic have their reasons for the trade limitations:
https://pokemongolive.com/en/post/jundevupdate-trading/
At this point the only people who would benefit from a Magikarp CD are newer players looking to complete their Mew research. Several other Pokemon deserve a CD before Magikarp.
A short message system would be an improvement. Even if a full-blown chat isn't implemented the fact that there's no real way to communicate with trainers in what's supposed to be a social game is pretty lacking. Being able to send pre-constructed messages for raid callouts or rare wild spawns would be pretty sick.