The way equipment can be switched needs to be altered somehow. Currently I can't figure out whether mid-game tool/class changes are a feature or a bug. At least when it comes to the class changes, I lean towards the latter.
I do think equipment and even the class should be changeable after the match has started, for the reasons stated in the previous posts. However I'd really like to see the change-process to be altered in a way that it feels like a feature rather than a bug. Perhaps a "switch role" button in the menu which pops up if one presses esc. Let players alter their role and spawn back on the ship with a delay of roughly 30s to prevent
abusive usage. If possible don't log them out of the match during the process.
Class and tool switching is already possible, I don't see why they don't implement a feature in-game that lets you switch class without leaving the match but also provides a timer penalty where you can't play, similar to the already existing afk feature. It could have other restrictions, such as once per game and only in the first 120 seconds of the game.
This sounds like a good idea to me. Situational equipment adjustments are a no-no. If your enemy makes you realize mid-game that it might have been a good idea to bring chem-spray against a flamer squid your lesson should continue until the end of the match. Adding an exception for late-joining co-captains might be needed though.