What happened:
I used an MCedit filter to change a structure into an (extremely) long command. I then pasted this command into a command block.
What I expected to happen was:
When I would click the button, the structure would appear after a ton of lag.
What actually happened:
The command did not get saved.
After looking into the development console, I found this chunk of error messages:
[21:47:25 INFO]: Client> [21:47:25] [Client thread/ERROR]: Couldn't send command block info
[21:47:25 INFO]: Client> java.lang.IllegalArgumentException: Payload may not be larger than 32k
I think that the new character limit is 32K.
Indeed, the limit was changed to "Many thousands of characters"
https://twitter.com/Dinnerbone/status/383683701814853632
Because, legitimately in a vanilla game (without third-party programs such as MCEdit), you wont hit that limit.