Ok I dug up Drayano's work.
Trainer's: Drayano changed some of the Pokemon for trainers, I've only changed the levels of the Pokemon they already had (using a formula i devised) to increase difficulty gradually.
Drayano made changes to Pokemon moves and stats. I refuse to do this as I feel it can bar the use of my games with legit games. (I prefer to keep things as close to the Gamefreak goal has possible)
Drayano added new items for evolutions and changed some existing items. I did not add items and simply used the existing items in new ways.
Drayano changed the location and availability of some items. I chose not to do anything like this as I had concerns i would be retracting from my attempts to gradually increase difficulty.
Drayano made some changes to the world. I did not do this, as again concerns for retracting from the difficulty, and also I did not want to change from the original game too much.
Drayano added some events. I would have liked to add events for some of the legendaries but I was, in a way, the test for HG/SS hacks. I started mine before everyone and had VERY limited knowledge for scripting. As scripting progressed after I finished the hack I decided not to go back. For non-event pokemon in my game you can catch as many as you want. If I started doing events for some of em, you'd only be able to obtain that one and that's it.
Drayano also made many small changes and even barred access to some areas. Again these are things I wouldn't do as I did not want to retract too much from the original game.
Well that's practically a 1:1 comaprison. Hopefully that fully answers your question. If you have any others, feel free to ask. (as long as you follow the rules of the forums)