I didn't see a thread already on this, so I wanted to post a few of the things I noticed when playing.
1) I don't believe currently you can join a game after it has started.
(Not sure of the oldschool specifics here, along the lines of being able to join until the game is half way over?)
2) Fixing bandages to consume at a faster rate
(certainly you should be able to consume bandages faster than what is in game. Currently it seems like eating food normally, I was thinking they should be 2-3x faster? Not sure)
3) Displaying Kills/deaths after the game
- On this its really just a gut feeling that it did this on oldschool, someone could confirm for me.
I've only played a handful of castle-wars games so I'll add anything else I see in the future.
Edit 6/24:
4) being able to attack players up on the castle walls from on ground level with mage/range
Cheers.