I don't have a full list handy, but some punctuation marks just don't work. I know this is a small issue in the big scheme of things, but it's annoying.

Agreed. It's actually pretty frustrating for the grammar/punctuations out there. It would be nice to be able to use a full key set of characters in legion comms.

I do think this is a big thing that needs improvement. The comm for individual ships has even less allowed characters then the legion comm has too.

I see at least one comma...

what game is that cuz it sure dont look like my version of galaxylegion

It isn't your version It is the in the next major upgrade.

Yeah, I'd really like to see commas, apostrophes and periods work properly at least for all comm methods.

They were most likely omitted because they interfered with special characters?
The way I'd fix it is code each special character and use this table to transmit data from client to server. It works

Mosts chats in the world allow all chars you can type, because it doesnt hinder the way you want to talk, by removing everything "special" other than the american a-Z,0-9, its being ignorant towards the rest of the world that has a couple other chars, and since the chat is limited to a certain amount of characters one might want to use & instead of using "and" ect. but since that gets removed one are forced to type and, also when talking about relays, you cant type +24 relays, but you must add another 4 characters to type "plus 24", and you cant use " either because it gets removed..

Percentage point character ... add that one...
%

Like I said, the most probable theory is that he is using these special characters for the client-server pipeline and in his rush to finish the game, adding a code table was not his first priority, so special characters are removed so that they will not interfere with client-server communication.

It takes more code to block/reduce char usage in this way, than take care of it straight of the bat and allowing all chars