I´d like to suggest a small qol improvement for matchmaking and team comunication. Nothing major just two small symbols next to the name indicating the primary and secondary role you actually queued for. Or something similar to the prfered pick preview for roles.
The main purpose is for people who got autofilled but it would be beneficial in other situations too.
Yes you could use chat but there are a lot of problems:
1.) It´s hard to keep track if there are more information like multiple people want to switch role, other important discussions or non gameplay related stuff ("prefer mid", "hi", "can jungle", ...). It´s just much faster and clearer if you can see what a person wants instantly.
2.) Backtracking in chat history ("wait what role did he want again?"). Chat space is limited and can scroll fast sometimes. By the time you check what someone said you might miss other information.