IV GTS

[Nekra]

I agree. These would be great features/filters for GTS.

-Trade with specific trainer
-IVs
-Shinines (if a trainer requirs a shiny)
-Nature
-Choosing if accept or reject a trade by depositor

In my opinion, six number password is user unfriendly. (Instead of choosing a person directly, you need a save way of communication to her/him. If you have not, somebody else may catch a password and snip a trade.)

Without filters mentioned above, no one can rely on GTS, if wants a rare or good stats pokemon.

I don't know how buttons are added into game, but a filter should not be hard to implement. It is based on simple conditions (if/else):
1) Test, if player choose a restriction.
2) If player chose a restriction, check it on other side, it is simple comparation.
If condition is not met, forgive a trade, else repeat the proces for another posible restriction.
3) If trade was not forgiven during checking process, all requirements are met and trade will be allow.

I am not sure how offline bugs may appear during development. About online (trade) bugs, I have a theory...
More players online->busier servers.
High amount of online players->servers do not have a capacity response all->get stuck->error.